Men are more than twice as likely to keep dating a girlfriend who has cheated on them with another woman than if she had been unfaithful with another man, says new research out of the University of Texas at Austin.
Women are the opposite: they are more likely to stay with a man who's dabbled in a heterosexual affair than be with one who has slept with another man -- these women fear homosexual sex is a very real prelude to their abandonment.
It's evolutionary, say the authors of the study, published last month in the journal Personality and Individual Differences.
Men, they explain, desire a variety of partners, while women crave commitment.
"A robust jealousy mechanism is activated in men and women by different types of cues - those that threaten paternity in men and those that threaten abandonment in women," lead author Jaime C. Confer said in a statement.
Translation? Another woman doesn't threaten a man's daddy status.
In fact, some men welcome another woman into the fold: these guys see a girlfriend's homosexual affair as an opportunity to have sex with more than one woman at the same time, an evolutionary bonanza, the authors say.
Translation? Men still believe in lipstick lesbians.
The researchers asked 700 college students to imagine hypothetical infidelities. Some were told that their partners cheated once, others twice.
Regardless of the number of extra-curricular episodes or partners, the study found that men demonstrated a 50 per cent likelihood of continuing to date a women who'd had a homosexual affair, versus a 22 per cent chance of staying with a woman after a heterosexual affair.
Women, in turn, showed a 28 per cent likelihood of staying with a boyfriend who had slept with another woman, versus a 21 per cent chance of sticking with someone who'd had a homosexual affair.
The authors say the findings reveal a telling (evolution-induced) hypocrisy:
"These findings are even more remarkable given that homosexuality attitude surveys show men have more negative attitudes toward homosexuality and [tend]to be less supportive of civil rights for same-sex couples than women. However, this general trend of men showing lower tolerance for homosexuality than women is reversed in the one fitness-enhancing situation-female homosexuality."