My girlfriend and I have been together for six months. Last Friday we were out drinking with some friends and somehow the topic of sex came up. Later that night, away from the group, she started asking me questions about how many girls I've been with. I tried not answering, but she wouldn't leave it alone because "it's been eating away at her". I gave her a range that I was pretty sure my number was in, and she got mad/jealous because it's a lot. It didn't help that she was a little drunk too. It led to her asking me if she meant anything and other stuff like that. I told her that I wouldn't be here if I didn't want to be, but she was still moping the rest of the night even after that. The next day she apologized for getting pissy. What should I say if this conversation comes up again in the future? Obviously she's worried that I'll lose interest in her since my number is high, but I don't want to get into stupid arguments about shit that has already happened.