We stated some simple rules WAY BEFORE they were of age to date. (That’s not to say it was perfect, many rules were broken, but at least they knew the rule to begin with)
Our very first rule was no dating until 16. None. No group dates either. They could go to a school dance and meet a boy there and call it a date, but that was about it.
Our second rule was that the girl or boy needed to come to our house for a family dinner for the first date. Then they would be required to participate in whatever “family fun” activity we had planned. Sometimes that would be watching a movie as a family, sometimes a board game, maybe bowling, making cookies, whatever we were doing they joined.
After that more freedom was given.
Third big rule is they can’t be in the others house with out parents home and the same rule is at our house.
I feel for you…my oldest broke all the rules just out of spite I think.

When we caught her “dating” and at the “boyfriends house” with out the parents home, we required all contact to be at our house. Car was taken away and we began to really track where she was. He didn’t last long. She grew into a responsible adult and now thanks us for all the restrictions.
While I agree with the other poster that many of these romances don’t last, please remember, babies do last a lifetime. And yes, it can happen…
Oh, and lots of prayers