One sociobiological explanation why women have the clitoris placed so that they don't orgasm during intercourse is so that they can see if men are willing to go out of their way to please them. A man who only selfishly wants his own pleasure and doesn't care about his partner's is not likely to be a very good mate in general for her.
^^^^^^^ CB: One problem with this sociobiological hypothesis is that at the time in which these traits arose, there probably wasn't monogamous mating, rather some form of group marriages.