Women with more male friends have more sex

Researchers believe this is because men see their partner’s male friends as “sperm competition”.

As part of the study, 393 men in committed relationships were found to have more frequent sex with their girlfriends when they perceive her male friends to be “sex rivals”.

And this was even more evident when men believed their partner to be sexually attractive to the other men in her social circles.

The men studied had an average relationship length of 35.9 months and were asked to report on their partner’s attractiveness, number of male friends and details of their sex life.

According to the lead author of the study Michael Pharm, this biological urge for sexual competition is a subconscious part of human nature.

He believes that men are more attracted to their partner when they estimate a greater potential for infidelity.

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“This does not mean that men want their partner to cheat on them. Rather, this means that if they estimate a greater likelihood of their partner’s infidelity, then they may (subconsciously) want to have sex with her to enter into the sperm competition,” he says.

“This is human nature. We need to be reminded that our partner is valuable to us and desirable to others.”

So it seems a little bit of healthy jealousy isn't such a bad thing as it helps maintain relationship satisfaction and a great sex life.