Ines Vuckovic/Dose

Better call Becky with the good hair, fur, scales, etc.

Humans are a pretty unfaithful lot. An estimated 50-60% of men cheat on their spouses during their marriages, according to a fairly shocking study by Joan D. Atwood and Limor Schwartz of Hofstra University. Women aren’t much better: Some 45–55% engage in extramarital sex. Unsurprisingly, that’s in line with the US divorce rate of 40–50%.

Scientists are little help. They insist the feeling of true love is no more than a rush of chemicals that flood our bodies when we discover a mate with good breeding potential. They’ve even broken it down into three stages.

This is your brain on drugs. | portishead1/Getty

First comes lust, brought on by estrogen and testosterone (which affects men and women, by the way). Then comes all-consuming, obsessive true love, brought on by dopamine, adrenaline and serotonin?—?pretty much a cocktail of cocaine and LSD delivered by Epipen. When we finally leave the bedroom, it’s thanks to the cozier hormone oxytocin, which bonds lover to lover but also parent to child. Men’s bodies also produce vasopressin, which some optimistically call “the monogamy molecule.”

“Essentially, vasopressin released after intercourse is significant in that it creates a desire in the male to stay with his mate, inspire a protective sense (in humans, perhaps this is what creates almost a jealous tendency) about his mate, and drives him to protect his territory and his offspring.”
?—?Dianne S. Vadney

That’s how it’s supposed to work, anyway. But we all know that once those first sexy chemicals fade, they often take our relationship status with them.

So we despair at ever finding true love, sometimes turning to the animal kingdom for confirmation that monogamy is even possible. A cursory search of the internet turns up dozens of listicles of monogamous animals, which are enthusiastically shared on social media.

There are some common stars of the clickbait. Wolves, Emperor penguins and beavers stay faithful, we’re told. But the undisputed star of the monogamy world is the humble prairie vole, whose tiny nervous system is positively shot through with vasopressin:

“Male prairie voles were given a drug that suppresses the effect of vasopressin. The bond with their partner deteriorated immediately as they lost their devotion and failed to protect their partner from new suitors.”
?—?BBC

All these animals, we’re told, mate for life: forsaking all others, till death do they part.

You cheating bastard. | Head Like an Orange/Tumblr

Get ready to be stung by cold, hard science once again: Research has shown that many animals we’ve previously thought to be monogamous, well, aren’t—at least not in the way we think of it.

“When we look hard enough at any living species, we find exceptions even in those that we used to think were fully, completely and reliably monogamous,” psychologist David P. Barash told The Globe and Mail. The proof, Barash says, is in genetic fingerprinting. In an uncanny echo of “The Jerry Springer Show,” DNA studies of offspring show that not all the genetic data is coming from one of the two parents. No, you’re not the father!

“Many species that were once considered to be truly monogamous really practice what is known as social monogamy. This form of monogamy is defined as pair bonding between a male and female, which mate with one another, raise offspring together and spend time together, but may nevertheless occasionally mate outside of their pair bond.”
?—?National Science Foundation

For example, Emperor penguins?—?lauded by evangelical Christians as paragons of monogamy after the hit documentary “March of the Penguins”?—?are really serial daters. Oh, they stay faithful to one mate, but only for one mating season. The following year they’ll be with some other penguin.

Eww. | von Nordmann/PD-US

Just about the only animal that would satisfy a Biblical requirement for lifetime monogamy is Diplozoon paradoxum, a flatworm that lives in fish gills. They don’t really have a choice. In adolescence, when the male and female join to reproduce, their bodies are fused. Even Romeo and Juliet might have chosen suicide over that.

When people find out that supposedly monogamous animals aren’t as monogamous as once thought, they’re often disappointed. It’s as if finding an echo of their monogamous aspirations in the animal kingdom made it somehow more likely to happen. As little as 3-5% of mammals even bother with social monogamy (just ask your dog). The deck seems stacked against us humans ever finding stable relationships.

But there’s no need to get discouraged. Studying why animals are monogamous, even for short periods, proves that sticking to one partner is often rewarded by Mother Nature. Those Emperor penguins, for example, stick together because the extreme cold demands cooperation.

While not 100% monogamous, some animals like the pygmy marmoset and the California mouse are “significantly more faithful than humans,” Barash says. In both cases, their offspring require a lot of care to raise. If they didn’t cooperate, their babies would die, and so would their species.

Beavers periodically form monogamous male-female relationships as well as partnerships with non-mates, so they can share the duties of maintaining their dams and keeping them clean.

It’s not much different for humans. We also practice social monogamy, largely focused on rearing our offspring. Scientists aren’t sure when human monogamy evolved, or why. In fact, only about 17% of human societies are strictly monogamous. (Though, even where other types of marriages are permitted, most people are in monogamous marriages.)

Keeping engaged can help keep you together. | Geber86

We humans do have unique factors in our favor, like religion, society and family culture. And as our lifespans increase, mutual elder care is becoming more important. Aging couples need to help one another pick up prescriptions, stick to healthy diets and get regular exercise.

Barash says one way to increase your chances of staying monogamous is to increase your stake in the relationship. Now, that doesn’t mean having a baby as a last-ditch effort to save a failing marriage. What it means is investing in things that require effort from both partners. That could be a child, grandchild or foster child. It could also be a family farm, a house, a business or creative venture?—?or taking care of each other as you age. That’s to say nothing of simple companionship, without which many of us wouldn’t be able to live happy, healthy lives.

As for urges to cheat? “Understand that you may have penchants for being non-monogamous but that doesn’t mean you’re not healthy or normal or that you don’t love your partner,” Barash told the Globe and Mail.

Barash may be on to something. He’s been married to his wife and co-author Judith Eve Lipton for 39 years.