New research suggests men and women have a similar ability to resist temptation, but men's resistance fails more often because they experience stronger sex impulses.

Researchers, divorce attorneys, and stand-up comedians agree: Guys have a harder time resisting sexual temptation. Studies suggest married men are more likely than women to have extramarital affairs, as well as to seduce someone else’s partner.

But why, exactly, do they engage in such behavior—which is often self-destructive, and almost always hurtful to those they love? New research published in the Personality and Social Psychology Bulletin provides a possible answer.

It suggests men’s ability to resist temptation is no stronger or weaker than that of the ladies. But it gets overridden more often because of the intensity of men’s desire.

“Brief sexual encounters could have resulted in greater reproductive success for men than for women in humans’ evolutionary past.”

In two studies, “men succumbed to sexual temptations more than women,” report Natasha Tidwell of Texas A&M University and Paul Eastwick of the University of Texas-Austin, “and this sex difference emerged because men experienced stronger impulses, not because they exerted less intentional control.”

The first study featured 218 Americans—70 men, 148 women—recruited through Amazon’s Mechanical Turk. Their average age was 32. All were instructed to describe a time when “you were attracted to someone who you felt it was wrong to pursue.”

They then answered a series of questions about the affair (or would-be affair), including the strength of the desire they experienced, whether they did everything they could to resist the temptation, and whether they ultimately acted on the impulse.

According to these self-reports, “Men were more likely to succumb to the sexual temptation, and this sex difference ... was a function of impulse strength,” the researchers write. “Men and women did not differ in their intentional control attempts." The men just failed more often.

The second study featured 600 undergraduates (326 men, 274 women). They performed a “partner selection game” while sitting in front of a computer. Photos of attractive or less-attractive potential mates flashed onto the screen in rapid succession, along with a prompt from the computer than the person pictured was “good for you” or “bad for you.”

Participants were instructed to accept the “good” partners (as determined by the computer) by pulling a joystick toward themselves, and reject “bad” partners by pushing the joystick away. Researchers noted when they pushed it in the wrong direction, or hesitated too long before making their choice.

They found men performed more poorly than women on the game, largely because they “experienced a much stronger impulse to ‘accept’ the desirable (that is, physically attractive) partners rather than the undesirable partners.” This difference “was much smaller for women,” they add.

To put it another way: Men performed worse than women “because they experienced a strong impulse to respond ‘yes’ to the desirable opposite-sex targets,” the researchers write, “not because they failed to exert intentional control over their responses.”

This all makes sense from an evolutionary psychology perspective, according to Tidwell and Eastwick. After all, they note, “brief, low-investment sexual encounters could have resulted in greater reproductive success for men than for women in humans’ evolutionary past.”

But while that urge goes back to our beginnings of a species, the ability to use self-control is relatively new, perhaps dating back no more than 50,000 years. If so, it’s not surprising that it is sometimes overridden by the deep-seated desire to mate with anyone who strikes a man’s fancy.

Perhaps in another 50,000 years, the self-control impulse in men will strengthen to the point where it can override the I-want-her impulse. But of course, that provides little solace to a woman whose mate is straying. This research doesn't give him license to do so, but it does suggest that it’s not a simple matter of trying hard to resist. He may very well be doing just that—and failing.