By Lauren Vinopal

Women are more likely than men to cheat on their spouses with a same-sex partner, studies suggest.

It’s not that women are more likely to be homosexual or bisexual — it’s that women appear more willing than men to change their minds about what turns them on, throughout their lives.

Men tend to choose a sexuality and stick with it, experts agree.

Women are wildcards.

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And it's this fluidity that can sometimes complicate relationships, contributing to divorce. 

“I think data are sufficient to suggest that more women are likely to change their reported sexual orientation depending on their circumstance, where men are more resistant to changing their identity from sexual behavior alone,” psychophysiologist and neuroscientist Nicole Prause, who studies women’s sexual responses, told Fatherly. 

The phrase “sexual fluidity” was originally coined by psychologist Lisa Diamond in 2008.

After following the same 100 women for a decade, she found that there were crucial differences between bisexuality and the sexual fluidity that otherwise heterosexual women experienced.

Bisexuality is defined as being attracted to men and women.

Many women, Diamond found, identified as gay or straight, but accepted the fact that they might change their minds at some point.

When experts say that women are more likely to be sexually fluid, they mean that they’re more likely to make an exception to, or even update, their sexual identities. 

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Of course, this does not mean that women are more likely than men to cheat on their spouses and sexual fluidity is seldom the main cause of a relationship souring.

As with any relationship problem, there are usually other, deeper relationship issues at play.

But now, more than ever, married women are stepping away from problem heterosexual marriages, and into same-sex ones.

“I have seen a mild increase in my own practice of women in their 30s over the last decade,” Sheryl Kingsberg, a professor and division chief of behavioral medicine in the OB/GYN unit at University Hospitals Cleveland Medical Center told In Style. “Maybe it’s hormonal, maybe it’s neuroendocrine — an epigenetic shift in brain chemistry that is hormone-based. But it’s certainly a shift.”

One hormonal explanation may be that women’s testosterone levels increase with age, and higher testosterone levels have also been linked with an increased incidence of homosexuality and bisexuality in women.

This might help explain why women may be more fluid in their thirties and forties, after having kids.

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Evolutionary psychologists have offered a number of theories as to why women may be more fluid as well, such as an adaptive way to decrease conflict in polygamous cultures.

Another popular explanation is that, because saying yes to intimacy comes at a higher risk and reproductive cost to women, they tend to make decisions more cautiously on a case-by-case basis, which could potentially allow for more deviation.

Still, it is likely that increased rates of sexual fluidity among women are primarily a social (rather than biological) phenomenon.

Indeed, there is emerging evidence that men have the same potential as women to be sexually fluid, but that stigma prevents them from acting upon it.

In most Western societies, women still face fewer social costs for same-sex relationships than men.

“I don’t know if one gender is more sexually fluid than the other,” clinical social worker Alisha Powell Powell told Fatherly.“But I think that one is much more widely accepted than the other.” 

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Lauren Vinopal is a freelance journalist who writes about health and science. She is a staff writer for MEL Magazine and has appeared in MTV News, Vice, GQ, and more

This article was originally published at Fatherly. Reprinted with permission from the author.