Winteraxy

My boyfriend honestly tell me he had a fling before. He gave me some details about it but not so much. I don't know what to think about this fling so I tried to forget it because it brings my mood down. But then, he unconsciously bring the topic where he said some details about their sex, and I told him to stop cause I don't like it. So after that he never mention about the girl, but suddenly I became curious. I don't know what to do, I want to know the whole story about them and I want to know how they ended to an argument but I was kind of afraid to asked. I want to know the girl's name but knowing him I think he wouldn't tell me. I wanted to asked him but I don't know if I should ask because I know it wouldn't do anything good but I can't help thinking about it. Kindly please tell me what should I do.