It is a scientific fact that women are not as horny as men are. Sex is not in the minds of women all the time as well. Therefore, women can go years without having sex. Women never pay for sex, because men are always so horny, that women will get sex anytime for free, if they want it. One of the reasons why females are not as horny as men, is because the female genitals are in the inside of her body, so it is hidden from view, and out of mind. Male genitals are on the outside, just hanging there in plain view, and therefore always on his mind. It's the same as a car parked outside the garage. If it's there, in plain view, you want to take it for a spin. If it's tucked away in the garage, it's out of sight, and out of mind.
I'm not saying they don't love sex as much as we do, just saying it's not always on their mind, and therefore not the highest priority for them.