Men have more sex—and better sex—when their girlfriend is a guy’s girl, not a girly girl. Best of both worlds, right? Eh, this is kind of a catch 22. The reason you’re having more sex is because of all her guy friends. You feel you’re competing for her attention and affection, according to a study published in the Journal of Comparative Psychology.

You want to remain the man on top, literally, and no one can blame you for that. In fact, this may be a good thing. Your lady enjoys more romantic attention, and you enjoy more sex, but there is a caveat. Though you’re in between the sheets more, you’re also fighting the sneaking suspicion that she’s being unfaithful.  

Lead study author Michael Pham told Fusion: “A lot of work shows that men are sexually aroused by their partner when they estimate a greater likelihood of partner infidelity.”

Researchers questioned 400 men in relationships, asking them to report on how attractive they found their partner, how many male friends they believed their partner has, and how attractive they believed these friends find her. The study found that the more guy friends you think she has, the most sex you’ll have as a couple. 

“We need to be reminded that our partner is valuable to us and desirable to others,” Pham told Fusion. “This makes us keep working at maintaining relationship satisfaction.”

While the study didn’t investigate whether your girl will initiate more sex if you have a lot of girl friends, it’s a pretty safe bet that striking up some jealousy in your partner will optimize your sex life together. Just don’t go overboard. The idea is to keep your girlfriend.

6 Things You Should Never Change for Any Female>>>