Your questioning is interesting. But I feel like I must offer an opinion so you can see this one from another perspective.
There are, in fact, self-interested women just as there are self-interested men. However, for both genders, something is expected to be offered. Culturally, man is the provider. For hundreds of years man has been seen this way: The one who hunts and brings home food, the one who keeps his wife and children safe, the one who protects, who fights and sustains. Just as a woman is seen as a Mother, the one who takes care of the house, the one who takes care of the children while the husband works, the one who cooks, etc...
To claim that the man doesn't be seen only as of the one who should sustain and protect the woman, you must be prepared to accept a woman who does not want to have children, who do not want to do housework, and who above all wants to be independent.
A relationship is about taking care of each other. Both have to have something to offer.