The greatest horror for a woman is to be pregnant with a bad man, and thus expend the energy, perhaps even a life of health, bringing up a child which has half of her genes and half bad genes. This is the ultimate root of why rape is a crime.
For a man, all sex is good. The more the better, as each encounter has the opportunity to share his genes. The quality of the woman's genes is less important, as it is generally trusted that she will at least attempt to raise the child. The responsibility, due to biology, is hers, and for a relatively short encounter and relatively little energy expended, the gamble is worth it.
These are inherent feelings, and probably present in all live-carrying females, and probably to a lesser extent in egg-laying species too.
