A study performed by researchers from the Department of Psychology at Oakland University in Michigan has found that the more male friends women have, the more frequently they’ll have sex with their partner.
The study consisted of self-reported data from 393 men in committed, sexually active heterosexual relationships. The participants were asked to answer a range of questions, like how physically and sexually attractive they found their partner, and how physically/sexually attractive they believed other men found their partner.
They also needed report how many male friends their partner had and how much sex they had in the past week.
The results revealed that the more male friends and male associates the female partner had, the higher the frequency of sexual activity.
So… why all the sex?
Researchers surmised that there’s an evolutionary reason for this phenomenon; Good old-fashioned sperm competition.
The human penis was not only designed to inseminate, it can also remove any potential rivals’ sperm. The more a man thrusts, the more sperm is removed; the more he as sex with the same woman, the greater chance he has passing on his genetic material while simultaneously reducing opportunities for his sexual rivals. Another tool in the male’s arsenal is sperm, and lot’s of it. Males who perceive a threat from a sexual rival will produce a higher concentration of sperm to overrun the potential baddies in their partner’s reproductive system.
Scientist also believed that males were also acting on a simple premise: The more sex she has with them, the less sex she’ll have with someone else.
There is one caveat. Males had more sex with their partners if they rated their partner as particularly attractive relative to the ratings other males gave their partners in the study.
“A lot of work shows that men are sexually aroused by their partner when they estimate a greater likelihood of partner infidelity,” Michael Pham, lead author on the study, explained. “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 sperm competition.”