because they still control who gets sex.
if you resent that, be less of a horn-dog.
every girl i've dated over the past 40+ years has been willing to "go dutch" because she wanted to get to know me. the feeling was mutual or we wouldn't have gone out.
the point being, each knew i wasn't into them just to get laid.
on those occasions when things turned romantic, we took turns planning and paying. whoever asks, pays.
if she didn't reciprocate asking, i figured she wasn't interested enough to bother with me, things stopped progressing, and i moved on.