Based on what data? There is no actual evidence of that. It's a myth made up by men - who mostly don't have the foggiest idea who the woman that rejected them ended up with. They are sure it isn't their fault because why would you want to engage in actual self-responsibility, so they blame it on women - but based on nothing other than that's what they decided. There is zero evidence of this dynamic.

Men think they are supposed to want multiple sex partners (and perhaps they would if they could figure out how to do that and still keep the relationships they want). But most men don't know now to do that, so they do what most women do and stick to monogamy, with some cheating in there. Women cheat as much as men do, so again, that has nothing to do with gender and women "wanting" monogamy more than men do. Again, 2/3 of monogamous relationships that open up do so at the request or instigation of women, who do want variety, but they also want it in a way that meets their other needs. Fuckboys are generally selfish, bad lovers, and shitty companions. Of course, they are boring. That doesn't mean that women aren't just as sexual adventurous and at the same time, in this culture, just as inclined to monogamy as men are.

If you want to know the numbers, read the story I linked. It's all in there.