Women do leverage sex for additional benefit, unless his attractiveness is drastically more valuable anyway. So... in a way.... brace for it... most women are prostitutes. The only difference is you've got a long-term contract going. The one where you can take him to the cleaners any time. That scam called marriage.
For the sake of argument, lets stick with the strictly economic form of hypergamy, i.e. women marry up economically. In male-female households, the woman usually earns more practically very little of the time.
So, lets say we minus the cost of a nanny, daily sessions with a shitty therapist, all his own expenses, and a housekeeper... what is the rest he's giving her for? Lets say she works part-time. Minus that too and it still leaves a hefty sum left over(in the salaries of most median earning men at least).