Relationships past

So I’ve been with my boyfriend for 7 months, he’s told me about his past without me asking. It really isn’t much, he and his ex were on and off and she cheated on him every time she broke up with him and would come back the next day. That being said- he has trust issues but I mean who doesn’t now days? I have had a past with several guys, some he knows about. But I don’t want him to know all because they were mistakes and I don’t want him to think of me any different if he does find out. Plus, those are mistakes that I don’t like thinking about. But anytime any male texts me or snaps me I can tell that he wonders if I have ever done anything with that person just by the way he talks. He says he trusts me and all but I just don’t know a way to tell him I don’t want him to know everything. He knows I don’t but he has said that he feels like I close off a lot of my life from him.