Title image for the post why humans have evolved to cheat

Why Humans Have Evolved To Have Affairs – an In-Depth Look

Statistics show that as many as one in three people will cheat at least once in their lifetime, and even though historically it is believed men have cheated in greater numbers, over the last twenty years the number of women cheating has increased by an estimated forty percent while the male rate has remained steady, meaning within the next decade or so it is possible that women will reach near parity if not absolute parity with men on the cheating scale. Meaning rather than moving closer towards monogamy humans are in fact moving further away from it.

But why, considering how destructive affairs can be and the fact that we are supposed to be an intelligent race, why have we not evolved to move beyond them, for example geese are monogamous, why have humans not evolved to be the same?

Some argue that the increasing rate of women who cheat is an inevitable result of female empowerment and the fall of the patriarchal system, and there is logic to that argument, for example, even today in some cultures should a woman cheat they risk being stoned to death. Considering this historically the risk reward for women when it comes to cheating was far more skewered on the risk side than it was for men. As this is changing is perhaps inevitable that more women will cheat.

But why is this inevitable, why as society changes are women simply catching up with men on the cheating scale rather than the opposite happening which would be men instead starting to catch up to women on the being faithful scale. This would surely be more logical, in which case why is it not happening?

The answer lies in why humans have evolved to have the ability to cheat, but before getting to that as ever with the Equations of Life Series I start with an equation:

In a relationship + wants something + not getting it/ can’t get it from partner + can get it elsewhere + has the power of choice + is willing to risk relationship to get what they want = cheating

With that said, let’s get to it and as this is going to be a long post I will break it up into sections, the first being why do people cheat.

Why do people cheat?

Most people would likely say that people cheat because they are selfish bastards/bitches who want to keep their partners all to themselves while being allowed to do as they please with others. As mentally pleasing an answer as that may seem, it doesn’t really answer the question of why people cheat, to which the answer is simple, because they want something the person they are cheating on their partner with has to give and are willing to risk their relationship to get it.

No matter what angle you look at it from, people cheat because they want something they are not getting and have found a person who can and will give it to them, that something may run deep and be born out of an unhappiness/ a feeling of neglect in the current relationship, or it may be that they have met someone that they simply desire more than their current partner, or it may be the result of a moment of madness in which a person simply got carried away, or it may even simply be a person likes to have sex with other people but wants to keep their current partner to themselves.

That is to say cheating is sometimes a result of nothing other than selfish want, sometimes just one of those things and sometimes an escape from an unhappy world that seems to have no escape. But regardless of a person’s reason for cheating, one thing is clear, everyone is capable of cheating the reason being we are not strictly speaking a monogamous race. We are in fact someplace between monogamy and polyamory, but the question is why have we evolved to be this way?

Monogamy versus polyamory

Imagine a world where your first relationship was also your last, that is the world of absolute monogamy. Regardless of whether your first relationship is with the person that is best suited to you, in a species that is entirely monogamous it is their nature to devote themselves to that person entirely for life no matter what. That means even if you’re completely ill-suited to this person you will still devote yourself to them and they to you and neither of you will ever leave because it is not in your nature’s to do so.

This means yes your partner will never cheat on you and you will never cheat on them, but at the same time your partner could be completely ill suited to you and yet you would lack the power to do anything about it because it would be against your nature to leave.

Considering this, and considering that statistics show that on average people go through five relationships before finding a partner that is suited to them, by not being an entirely monogamous race we have the power to end a relationship that is wrong for us and search for a one that is right for us, which is most definitely beneficial. So for any person who has left an unhappy relationship they have the fact we are not an entirely monogamous race to thank for that.

And this is where our polyamory traits come into their own, whereas monogamy is like a gun with only one bullet in the barrel meaning if you don’t strike the bull’s-eye with your first shot you don’t get another one, polyamory is like a gun with unlimited ammo, if you screw up with one shot you’ve always got another bullet in the barrel to try again meaning you can keep trying until you strike that bull’s-eye.

However, just like with monogamy, where its greatest strength is also its greatest weakness, polyamory is the same. For example in a race which practised absolute polyamory relationships would be far too interchangeable and thus nobody would truly build up any form of loyalty to each other. For example, screw up and can’t be bothered to deal with the consequences, no worries you can just replace that person with another. Same as if your partner gets sick, you word have no need to stick around because you word have no true connection to that person in which case it would be far more logical to replace that person with someone who is not sick.

In a world of absolute polyamory nobody would build up a strong bond with anyone meaning everyone would be entirely replaceable meaning nobody would ever mean anything to anyone. In this is the greatest benefit of monogamy, by being able to build up a strong bond with a person you are able to create a world where that person will show loyalty to you and you will show loyalty to that person and thus you will both stick around and look after each other which is most definitely a good thing.

This is why the middle ground is where humans are at, it is highly beneficial to be able to build up strong bonds with individuals which monogamy allows; however, it is also highly beneficial to be able to break those bonds should they prove to be detrimental and replace them with bonds which are beneficial which polyamory allows. That is to say there is a benefit to being sort of monogamous but also sort of polyamorous, but there is also a downside. Only a race which has evolved to practice by nature absolute monogamy or absolute polyamory will by nature be one hundred percent faithful, which is why humans are able to cheat. Which means we have not evolved to cheat per se it is just we have evolved to merge monogamy with polyamory and as a result of this by default have also gained the ability to cheat.

The environment factor

Humans are masters at adaptation, and what we are best at adapting to is our environment. That is to say if we live in an environment that benefits strict monogamy then we will become a society that practices strict monogamy; and vice versa, if we live in an environment that benefits a less strict form of monogamy then we will become a society that practices a less strict form of monogamy.

This is another benefit of being in the middle, we are able to adapt our relationship practices to best suit our environment. If we were strictly monogamous by nature or strictly polyamorous this would be far more difficult, but by retaining our middleground roots the change becomes less troublesome. That is to say we have evolved to become a race that knows how best to survive in whatever environment we live in and whatever environment we live in will dictate whether we have a more monogamous or polyamorous approach to relationships.

This brings me to today and why cheating is on the rise. Thanks to globalisation, the Internet and mass dating tools like Tinder, we now have more options than ever before in history while at the same time our environment is simply making it less of a necessity to require a partner. And our environment is key.

In the past the environment was most definitely more suitable to monogamy, having a partner simply gave a person a far greater chance of survival then not having a partner. Also for raising children the stability of a monogamous relationship was an absolute requirement.

That is to say in the past it was vastly superior in regards to raising children to have a home in which both parents remained together and not just remained together but got together as soon as possible. That means a world in which it takes five relationships to find a partner which is the world we are becoming would not be viable, reasons include for starters the sheer lack of healthcare back then. The majority of women in the past if they wanted to have children needed to have their children in their twenties, preferably their early twenties the reason being due to the lack of available healthcare if they waited any longer there was a high probability they may not be able to have children at all. That meant finding a partner as soon as possible and sticking with him was of the utmost importance.

This is why it is highly likely that religion focused so much on the importance of monogamy and arranged marriages and was so venomously against divorce. Because for the human race to survive men and women needed monogamy. Any study into the hardships that the average woman whose husband died faced raising her children alone is testament to this need. And it was not just the average woman whose husband died, for the average man whose wife died that man and his children would also face extreme hardship. That is to say the best world in which to have children and then raise those children in the past was a world in which men and women got together as soon as possible and stayed together for as long as possible.

Inevitably this created an environment in which men and women alike were far more likely to tolerate being with people who were ill suited to them, because in doing so they were giving their children the best chance of surviving. And surviving is the word, in the past it was not just about giving them a better future it was about them surviving long enough to become adults.

However, thanks to the immense technological and societal advancements of the last two hundred years a single parent is able to raise a child without any trouble at all. Also, a woman is able to have children into her 40s now meaning there is less need to find a partner as quickly as there was in the past.

That means that relationships in this day and age have become less about survival and more about happiness. That means we are all a hell of a lot more picky than we once were, because we have far less incentive to not be. In the past we would pick a partner as fast as we could and find a way to make it work no matter what because our survival and the survival of our children depended upon it, today it does not.

And this factor was even more relevant for women than it was for men, which is likely why in the past women were far less likely to cheat than men, because the relationship was more important in regards to a woman’s survival than it was to a man’s. That is to say due to the patriarchal style of the old world, along with the just plain and simple brutal nature of the mediaeval world, a woman was far safer with a man then without. Now a relationship is no more a requirement in regards to safety for a woman then it is for a man, hence, why the female rate is fast catching up to the male.

So the numbers of people cheating is not increasing because we are evolving into a race that is more likely to cheat, they are increasing because firstly men and women are becoming more equal which means women are able to cheat just as easily as men now, and secondly due to the Internet and the ease of access to people it brings, it is so much easier to cheat and get away with it.

Which means the reason cheating is on the rise is simply because more of us who want to cheat are now not only able to, both are able to do it with increasing frequency. Which means a key factor in regards to cheating is the environment in which we are living. If an environment is more conducive to cheating then more of us will cheat and vice versa.

But that doesn’t really answer why any environment is conducive to cheating. We are able to cheat because we are in the middle ground between monogamy and polyamory, and our environment will dictate the amount of people along with the frequency people will cheat at, but none of that answers why humans have evolved. Why does any environment lead to people cheating? Is there a reason or is cheating just one of those things where there is no benefit for the action it is just the action is the result of something that does benefit us?

To answer that, we need to firstly look at why humans would choose in the first place to have sex with more than one partner.

The diversity factor

Statistics show that a stable home environment with both parents remains the optimal environment for children to be raised in, which is often why couples who have children will try so hard to save a troubled relationship. It is also why couples who have fallen out of love often remain with each other despite having fallen out of love, a scenario in which statistics show frequently leads to affairs.

This likely helps explain why statistics also show that as many as one in fifty children may have a father that is different to the one reported on their birth certificates. But it does not explain why a person should they want to remain in a stable environment would risk that environment by having an affair. That is to say if a person wants to stay in their relationship for the sake of their children why risk that relationship by having an affair?

At this point I could talk about psychological needs, that is to say I could go down the line of people have needs and if their partner is not meeting those needs, but they don’t want to leave or cannot leave their partner for whatever reason then having an affair may seem like a good idea. But if I did it would not answer the question of why we have evolved not to simply sacrifice those needs to keep the relationship alive. How could any need from an evolutionary perspective possibly be conducive to a person having an affair?

Before going on, I just wish to add as a disclaimer this is a perhaps a bit of a tetchy subject line as it implies there may be an evolutionary benefit to cheating but in the interests of creating a fully rounded view I feel it necessary to include it, so if you are easily triggered I suggest you skip this section.

Diversity brings with it immense benefits in regards to the strength of the human gene pool, and diversity as it happens is another benefit of polyamory as it creates a world where people have children with more than one partner.

However, as said absolute polyamory is a bad thing because it would lead to unstable environments which are terrible for raising children in. So in a perfect world from an evolutionary standpoint both diversity of the gene pool along with stability is wanted. That is to say a world in which a child is raised in a stable home environment but adults have children with more than one person is a greatly desirable world from an evolutionary standpoint.

This is likely why we are seeing more of what is termed blended families, that is to say families where one or more of the parents bring with them children from a different relationship. Families like these are on the rise at the expense of conventional families, and are proving to be equally as functional.

Rather ironically however, this is likely why we are seeing more broken families, people are sacrificing what they deem as an unhappy and thus unstable environment in the hopes that by doing so that they can find a happy and thus stable environment elsewhere. That is to say because blended families are proving to be viable alternatives people have less reason to fear that leaving an unhappy relationship will harm their children, and in some statistics it shows that leaving an unhappy relationship may actually be beneficial to children.

Considering this you would think people would see less reason to need to cheat as a result of being in an unhappy relationship, and thus the cheating statistics should be falling yet as said for men they remain stable and for women they are increasing rapidly.

This is because statistics show that the main reason people cheat is not the result of an unhappy relationship but instead sexual dissatisfaction. That is to say if the partner gave them more sex than they would be happy or in some cases if the partner let them have sex with other people but was willing to remain faithful themselves they would be happy. That is to say they are happy with the relationship they just want more sex, in some cases from their partner in other cases from other people, and it is the fact that that desire has gone unheeded that has led them to cheat.

That is to say they are in a stable and happy environment they just want more sex and are willing to risk their relationship to get it. The question is from an evolutionary point of view why would humans evolve to risk a stable and happy relationship just for sex? It seems completely and totally illogical and entirely self-defeating.

The question is though is it? The answer to that is both yes and no, carried out in large numbers it is most definitely self-defeating but it is arguable from one perspective if that carried out by only small numbers of the population there may just be a benefit.

Imagine a world where everybody was in a stable and happy relationship, and in that world every person only has children with their partner. From the perspective of us as individuals, that would be a great world because we would all be in happy relationships and none of us would have any fear that our partners would cheat and we would feel no need to cheat. But some argue that from the perspective of the human race as a whole this would be bad in regards to diversity of the gene pool.

To explain, there is much evidence that genetic diversity is a very good thing, that is to say it is beneficial to have as diverse a gene pool as possible, or rather the greater the diversity of a species gene pool the greater that species survival chances. From helping us ward off viruses and disease, to much more diversity really is king. And one of the best ways to increase diversity is for men and women to have children with numerous different partners.

However, as said statistics show that stability is extremely important for raising children, and for this reason some argue that you get the explanation for why as many as one in ten children have a different father to the one reported on their birth certificate.

For example, imagine two couples, both have one child each with their partners, but then both have affairs with each other’s partners and the women become pregnant, but neither the men nor women realise that the women have become pregnant as a result of the affairs. That is to say both couples believe that the children are their own.

In this situation from an evolutionary standpoint we have the best of both worlds, we have diversity as a result of the fact that both the men and women have had children with two different people, but we also have stability because those children will be raised in a stable monogamous relationship.

However, should the affairs have been found out the men would likely not have raised the children which were not their own but would have instead favoured raising the children that were their own which would mean the children would be raised in a less stable environment than the one where the infidelity went undetected.

The benefits of this practice are actually seen in the wild in wolf packs, lone wolves often have affairs with female wolves from a pack, the new-born cubs gaining the benefit of being raised by the pack while at the same time the gene pool gaining the benefit of diversity.

So affairs from an individual standpoint specifically the individual who has been cheated on are most definitely not a good thing; however, from an evolutionary standpoint where the human race is treated as a collective it is arguable that there may just be benefits to small numbers of people having affairs. Whether those arguments hold water is down to the individual to decide, but they are plausible hence if a rounded view is to be made are worth considering.


Regardless of whether there are any evolutionary benefits to being able to cheat, or whether cheating is simply the price we pay for being in the middle of monogamy and polyamory, it is close to indisputable that there are benefits to having both traits of monogamy and polyamory. This is why humans along with the majority of species find themselves someplace between both monogamy and polyamory, that is to say we are sort of monogamous but also sort of polyamorous, meaning we are never in a strictly monogamous or polyamorous relationship we are always in both which incorporates a bit of both.

This is why even those who choose monogamy are not entirely choosing monogamy, the reason being we all have the power to leave should we decide that the relationship we are in is not working, and as long as a person retains that right they are not practising absolute monogamy they are simply choosing to remain faithful.

The best way to think of it is to imagine a line which stretches from 0 to 100, with absolute monogamy being zero, and absolute polyamory being one hundred. Geese would probably be somewhere between ten and fifteen on the scale, while humans, it’s a fair bet that the majority of people would find themselves someplace between thirty and seventy, meaning some humans are more monogamous than polyamorous and vice versa. But none of us are truly monogamous or polyamorous.

For example one person may find themselves at thirty on the scale, meaning they are more monogamous than polyamorous, and vice versa another person may find themselves at seventy on the scale meaning they are more polyamorous than monogamous. Another may find themselves right in the middle at fifty. But none will ever find themselves at absolute zero. If they did then they would care about nobody but their partner.

For example, in a world of absolute monogamy people would have no close friends outside their partner, and it is arguable that in a world of absolute monogamy a person would put their partner before even their children, which would most definitely not be a good thing.

So if humans were a one hundred percent monogamous race, they would practice a life in which only their partner mattered even if that partner was not right for them, meaning no other friends just acquaintances, while if humans practised absolute polyamory nobody would matter to them, meaning the fact we are not entirely polyamorous is the reason we are able to build up strong bonds with people full stop and the fact we are not entirely monogamous is the reason we are able to build up strong bonds with people other than our partners, and while sometimes those bonds we build up beyond our partners will be just bonds of friendship, other times those bonds will lead to affairs.

Meaning the reason the most likely reason that a person is able to cheat is for the same reason that a person is able to leave that cheat for cheating and move on with another partner, because by not being entirely monogamous or entirely polyamorous we have been gifted with the power of choice. And through the power of choice are able to adapt our mating practices as best we can to the environment in which we live. In the past that environment suited monogamy at all costs, in the present it suits a more balanced and nuanced approach. But the price of that adaptability and the price of not being either completely monogamous or completely polyamorous is the fact that we all have the power to cheat.

Which means we have not evolved to have affairs, we have simply evolved to have the ability to choose the optimal relationship style for our environment, which means we have evolved not to cheat but to choose based on our present environment what is right for us. That means the reason some people cheat is for the same reason that the majority don’t cheat, because people have the power to choose what is right for them, and just as some people will use that power to stay faithful others will use it to cheat.

That’s all from me for today, stay safe!

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