If you want to talk about the evolutionary/biological theories about the differences between men and women, then it can be said that men have an innate fear of independent women because they know that if a woman can take care of herself, then she has no need for the man except to biologically accept his seed. Therefore, a man's unconscious anxiety over being abandoned by the woman is strongest and most prevalent, after a couple has sex. The more the man is aware of his need of security, the more this man will be insecure about those he gets closer to. This is the type of male personality most likely to abandon women emotionally after sex, or take no responsibility. This man will also claim that the separation was due to his drive to conquer, this is more of an angle for him to perceive the situation so he can give himself a sense of empowerment.

This would have to be the theory that would have to complement the theory that men are biologically programmed to spread his seed in an evolutionary urge and thus, this desire causes monogamy to be counter-intuitive to men.

I think both theories, despite being somewhat semantically paradoxical, co-exist on equal planes.