Most of human evolution occurred before the advent of birth control pills or paternity tests. This gave both genders certain advantages and disadvantages. If two people are monogamous and the female gets pregnant there is no doubt who the father is. If the female is monogamous but the father cheats then there still is no question who the father is, but if a woman has sex with two men in the same month and became pregnant by one of them even she would have no idea who the father is. So that sucks for women.

Conversely if you had and island with 50 women on it and one man within a year you could have as many as 50 babies (maybe more if all women are fertile and some have twins), but an island with 50 men and one woman could expect to produce about one baby every nine months or so. So men became the expendable gender. Being the expendable gender means that when it came time to protect the tribe from lions, tiger and bears (or even worse invading tribes) men were the ones who had to fight. That sucks for men.

Testosterone is the hormone that feeds the libido in both men and women. It is also the hormone that plays the biggest role in a person's physical strength. Men who possessed more testosterone would be more useful on the battlefield for this reason and would be expected to breed more not only because they would survive longer but because testosterone would drive them to do it.

One thing men and women have in common is that we would give our lives to protect our children, so one of the best things a woman could do during the lawless days, that defined all but the last few thousand years of the 200,000 years in which homo sapiens have walked the earth, was to find a strong man and have children with him to assure his protection. The only challenge to this plan was that she would have to leave him no doubt that her children were his and the easiest way to do that would be to not cheat. One of the dumbest things she could do would be to sleep around, get pregnant and have no idea who the father is, because even if a man might protect a child on the vague chance it might be his, he isn't going to put forth the effort he would if he knew for a fact the child was his.

So if you're ever curious why men are celebrated for being promiscuous and women are demonized for it, why virginity up until marriage was such a big deal or why slut shaming exists and why these dynamics pop up in one culture after another no matter how isolated they are from each other, now you know. It isn't fair, but for the vast majority of human history it was the best choice we had.