Ann Friedman asks "whether men are more likely than women (or vice versa) to have strong social support networks" and tentatively concludes that women maintain stronger friendships:
According to the Encyclopedia of Women and Gender (there's a reference book for everything!), "one of the most consistent findings in gender research is that men invest most heavily in their wives as support providers whereas women most often turn to women friends and family for support." This is probably why men suffer more than women in a break-up.
From an early age, most women are socialized to be more nurturing and relationship-oriented than men, so perhaps this isn't surprising. My guess is that homophobia also plays a huge role. Men are taught to perceive intimacy with other men as gay. You can see it in trend stories about "man-dates" and movies about male friendship, which often veer pretty quickly from depictions of platonic affection to defensive homophobia. There's even a social stigma attached to cross-gender friendships. Just ask Slate's Juliet Lapidos and her best friend, Jeff. Or me and my bestie Josh. (No, he's not gay. No, I'm not gay. No, we've never dated. Yes, we are super tight.) If all of these relationships are socially off-limits, who's a man to befriend?
(Illustration: Fab.com cards.)