When men learn that women have casual sex with more attractive guys and make rules for them to have sex, they believe that the woman is not actually attracted to them and is only interested in him for the security and company he provides. And us choosing them only because they can't land the more attractive guy.

And so men demand sex sooner to make sure that the women is actually attracted to them.

OTOH, when men demand sex sooner, women fear being used for sex and then discarded. Its unpleasant to be used as a sex object when women were hoping for a romantic relationship.

So how to fix this?

Simple, women should stop having casual sex. No man would demand sex sooner if all the other men invested the same time and energy he invests. And if a man still demands sex sooner, women can learn that he's only there for sex.