People really don’t understand the history. Social practices evolved over the centuries and were as subject to evolution as anything genetic. Most traditional social practices evolved for a reason. Often practices stick around long after those reasons no longer apply, but they evolved for a very good reasons in the first place.
As you note, pregnancy is inherently dangerous to a woman’s health, permanently alters her body, and has a permanent and profound impact on her life. And this has always been the case.
Think about how promiscuous women have traditionally been treated. Whore. Slut. Harlot. Women were expected to be chaste until marriage. Meanwhile, promiscuity was often accepted or even celebrated for men. The reasons for this disparity are likely multifaceted, but one likely reason is that sex had such a high risk for women and girls. Think of the mother who calls her own daughter a ‘whore’ for the way she dresses. Who does that to their kid? Someone who thinks they’re doing that kid a favor. Traditionally, mothers expected their daughters to be chaste and conservative, and often that was to protect them from the inevitable risks that came with sex. Women have always had far more to risk when it comes to sex than men.
Effective contraception and abortion access changed this. It was only once the very real risks of premarital sex were ameliorated could modern straight casual sex culture emerge. Yes, some flings did happen in 1850, premarital sex did happen. But it was much rarer, and it was mostly among people who were already on the path to marriage anyway. There were not mixed-sex bars in 1850 that you could go and try and find a partner for a casual fling. Men could go hire a prostitute in most towns and cities, but the idea that a respectable woman would meet a man, alone, then go to his house and have premarital sex that night? That’s the kind of thing that could literally end up in the town newspaper the next day.
Contraceptives - the pill, IUDs, condoms, and abortion; these are foundational technologies to modern sexual practices. They are as important as to modern dating culture as the automobile is to a suburban land use culture. When sex means pregnancy, it means you should never have sex with someone unless you are prepared to spend the next 20 years together raising kids. And yes, that means the casual dating scene is going to take a big hit.
