I think it has something to do with the way women create relationships. Females have a web of relationships while men are more narrow. It seems as though women go through many different friends throughout their lifetime. Men on the other hand tend to have long lasting friendships since childhood. I think this is because women and men have friends to fufill different needs.
Women have friends for support and guidance, comfort and care.
Men seem to have friends to hang out with when it is conveinient. Since women do spend so much time and are so involved with their friends, maybe this is why there is so many conflicts.