I think a lot of people have this idea that until the 50’s 60’s (or whenever) people were not promiscuous and having sex.
Based on what I have seen in my life and what my folks and other older acquaintances have told me things have not changed that much, it’s just in more recent times it’s been more openly accepted and or discussed.
In reality it’s a lot harder to hide these days with our pervasive technology.
People are a lot more promiscuous today. I've lived a long time. It's definitely different. If a woman was having sex in the old days before the Pill, it was most likely with the person she ended up marrying, either because they had that understanding or because she got pregnant.