Back a few 100+ years ago a womans sex was roughly equal to a mans commitment. This is before the time of promiscuous random sex. The man must show he is committed to the woman in order to get sex. A man may still have had sex with prostitutes prior to the marriage but the woman was generally a virgin if she was to be respectable enough for marriage.

Now sex is freely available outside the constraints of a relationship. This in effect devalues sex. Commitment is still worth the same and as such the sex must be amazing or the woman must show she offers a more valuable package to be worth that commitment. A slut sex may be worth 0.001 of that girl who has only slept with her previous bf. This is effect makes it harder for the slut to secure the relationship with a man who is worth something.

This is a reason women lie about the number. They devalue their sex when they say they have higher numbers.

These numbers and ratios are all individual to different men but the idea remains the same.

Too add. This is conversely the same of a mans commitment. If a low value man or any man offers his commitment freely well then his commitment is worth less. 0.001 to that of a womans sex. This is why orbiters cannot get the sex from his planet or whatever you wanna call it.

To illustrate the point further imagine both the man and woman are standpipes being steadily emptied of water. A womans sex will fill up the standpipe and a mans commitment acts will fill up this standpipe. If either standpipes empty then the relationship will likely end. A woman who has worthless sex will have to work harder to stop this emptying.