Wow - when exactly did this become a “rule” to have sex on the third date???

Not that I haven’t had sex on a third date ( or a first) - but really, shouldn’t it happen when you’ve learned enough about the other person to know that they won’t murder or stalk you, give you an STD, boil your bunny or get “accidentally” pregnant? And that can take highly variable amounts of time.

Heck, I’m a product of the promiscuous 70’s but even then three dates was kinda early and certainly not expected.