Why are we monogamous?

A brief history

Where do our modern notions of monogamy come from?

In fewer than 10% of species it is common for two individuals to mate exclusively. While 15-29% of primates favor living together as couples, far fewer commit to monogamy as we know it. Interestingly, anthropological records indicate that approximately 85% of human societies have permitted men to have more than one wife, whether it was because a first wife had fertility issues or wealth allowed for multiple wives. A related but separate thought—I always wonder what women would have done if they made the rules all those centuries ago. Would they have wanted multiple husbands? Anyways.

The origin of monogamy in humans is hotly contested by scientists and anthropologists alike. There are countless theories and research studies I stumbled upon in my rabbit hole so I pulled out a couple of my favorites to share with you. Note: The below theories do not account for same-sex relationships that have obviously evolved in tandem.

Did STDs kill the vibe?

Monogamous culture has only been around for the past 1,000 years. Evolutionary anthropologists suggest that the earliest primates—alive as early as 75 million years ago—were solitary and preferred to live in isolation, only coming together to mate. As time passed, primates became more social and evolved to live together in groups, but only humans solidified true monogamy. Today, primate species such as bonobos and chimpanzees still mate with multiple partners.

Studies suggest that monogamy was evolutionary. It helped preserve an individual’s health and their population’s health. So—did STDs kill polyamory? Not quite. In early hunter-gatherer societies, of 30 people or so, STD outbreaks would have been short-lived with no significant impact on a population. However, as agriculture developed and societies grew larger, STD rates would have been high enough to cause infertility from infections like syphilis, chlamydia, and gonorrhea (according to the research), and of course, no treatments were available.

Monogamy is money

Alternatively, as agriculture and farming boomed, people may have opted for monogamy to preserve their wealth through marriage. Marriage has obviously followed a similar path throughout the years, with tax benefits following marriage even today. “Pair bonds,” as scientists call monogamous relationships, were a crucial adaptation that arose in an archaic forebear and became central to human social systems and our evolutionary success.

Females prefer reliable providers

If we look even further back, studies suggest it is entirely possible that even our most distant ancestors were monogamous. According to this hypothesis, an ancestral polygamous mating system was replaced by “pair bonding” when males diverted energy from fighting one another and toward finding food to bring to females (as an incentive to mate). Females preferred reliable providers to aggressive competitors, ultimately choosing to bond with the better foragers. Shocking!

Monogamy = crime reduction?

Interestingly, a number of studies show that men commit fewer crimes when they're in a monogamous marriage. The theory goes: When intrasexual competition is suppressed, and the pool of unmarried men shrinks, normative monogamy can actually reduce crimes like rape, murder, assault, robbery, and fraud.

Your take

But even knowing some of the evolutionary and social reasons for monogamy, it doesn’t take away from the fact that maintaining a monogamous relationship can be challenging, especially as societal norms and gender roles continue to shift. For example, in heteronormative relationships, as women gain more financial independence and are less dependent on men, traditional power dynamics in relationships have been upended. Additionally, the rise of social media and dating apps has made the temptation of potential partners outside of a monogamous relationship easy to access.

So I want to know—are you in a monogamous relationship? Have you been married for decades? If so, how? Were you ever tempted to venture outside your relationship? If you’re polyamorous, how do you cultivate your relationships? Are you in an open relationship? Do you get jealous? How about swinging? Have you ever cheated and not told your partner about it? Have you cheated and told them, what happened? If you have thoughts, tips, stories, or wisdom from any side of the table, I’d love to hear them, anonymously, in Diem here.

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