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Over a lifetime, 90% of men and 75% of women cheat on their partner
Last reviewed: 01.07.2025
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"About 75% of Swiss people have a regular partner. Most would like to get everything in this relationship: emotional attachment, stability and sexual satisfaction. As family therapist Klaus Heer says, love is monogamous, but a person is not. In surveys, 36% of women and 44% of men indicate that they have had sex outside of a regular relationship," writes Swiss journalist Michelle Binswanger. Some experts say that 90% of men and 75% of women "go left" in their lives. Infidelity is one of the main reasons for the mass breakdown of marriages in Western industrial countries.
But the crucial question is not why we can't be faithful, but why the ideal of our relationship is based on a lie. The lie that we will be faithful to each other forever.
In love, we think of ourselves as the noble protagonists of Romeo and Juliet. But when it comes to human sexuality, the truth is more like Planet of the Apes. Despite our romantic minds, our species is obsessed with sex. Every day, billions of dollars are poured into the sex industry worldwide. Pornography and prostitution, portals for finding partners for life and one-night stands, pharmaceutical companies and family therapists make money by alleviating the symptoms of our illness, but do not get to the root of it. The modern PR manager who orders a vegan lunch before going for a pedicure is much closer to his hairy ancestors than he would like to think. This is why our culturally conditioned models so regularly lead to failure.
"I've seen too many relationships fail because partners have unrealistic expectations of fidelity. And I wonder if marriages fail not because of infidelity, but because of unrealistic expectations that sex will only happen within marriage?" the author writes. "Why do we think it's more normal to rush from one short monogamous relationship to another than to focus on extramarital sexual encounters? Why does the pattern known as 'serial monogamy' seem more appropriate than saying goodbye to the dogma of monogamy?" "Darwin defined the standard model of human sexuality that evolved over the course of evolution as follows: a man is genetically predisposed to disperse his abundant seed as widely as possible, while a woman carefully guards her precious reproductive organs and eventually accepts the male she deems suitable for raising children. A man must refrain from infidelity so as not to waste energy on other people's children, and a woman wants to ensure that a man does not share his resources with other women," Binswanger says. However, according to her, evolutionary psychologists Christopher Ryan and Casilda Jeta in their book Sex at Dawn say that these patterns indicate cultural adaptation to the social conditions of patriarchal societies.
The evidence is that the ancestors of modern humans also copulated with other hominids. This is even reflected in our genome, which contains up to 4% Neanderthal DNA. It follows that such relationships led to the appearance of children who were raised and accepted into prehistoric communities. If our genetic program really worked as described above, then mixed hominids would hardly have a chance of survival.
The author, citing Ryan and Jeta, says that the situation changed with the advent of sedentarism. "The concepts of property, wealth and inheritance emerged. To ensure that the fruits of their hard work would be enjoyed only by their biological children, men had to ensure that their wives did not have sexual relations with anyone else," the author writes. "With Christianity came a rigid moral corset that completely shackled female sexuality."
"The fact that women have always been more careful in choosing partners than men, because they always had the risk of pregnancy, says nothing about their sexuality. And the invention of the contraceptive pill and emancipation revolutionized women's sexual behavior," the author writes. According to sexologist Ulrich Clement, differences in sexual behavior between the sexes have been reduced to almost zero.
Our desire for a long-term and close partnership is ultimately a desire to find a family and a home environment. A normal human desire. Perhaps it would be worth recognizing that sexuality is also, to some extent, our home environment and that we have the right to live in accordance with it.