How would you feel? (Long post, need to vent)

I feel like I should just move on and not take it so personally, but I can’t stop thinking this and I’m just not sure if I’m overthinking it. So back story, I was first assaulted at 6 by a group of neighbor boys. One of them made me touch his penis with the other boys surrounding me and I still remember to this day how I felt in that moment. My mom also told me that I had ran home and told her that they held me down and touched me, but that part I don’t remember. Since then I’ve always had trust issues when I came to boys and specifically boys, not men. I’ve been sexually assaulted several other times and those happened in college when I was 18. So then I ended up leaving my college, came home and met my boyfriend. I get triggered during sex sometimes and I’ve come to realize that I’m comfortable with my sexuality, but just not with others. Specifically when it comes to porn. It gives me anxiety and makes me want to cry. It’s taken a few years for me to be completely transparent about everything that has happened and how that has affected me because I was still figuring it out, but now my boyfriend knows everything and now he understands my view on porn and why I have those views and respects that and stopped watching and looking at all of that because he realized it was an unnecessary habit and that it was affecting our relationship. Well one of the last serious talks we had, he told me that when he was younger, he showed his younger cousin (who is like 5 years younger than him) his penis. He said he was just horny and not thinking, but he knew it was wrong and has never told anyone that, but me. I think he told me because he feels ashamed and wanted someone to vent to, but I can’t help but be so upset about it. I’ve talked to my therapist about it and she’s told me like boys do that kind of stuff without thinking and it’s normal for young children to explore, but I feel this situation is much different. He doesn’t remember exactly how old he was, but he wasn’t like 5. He was probably like 12 or so. I totally had an emotional break down last night and told him I can’t stop thinking about it and thinking about her and that I just want to know if she remembers or how she feels about it. Like I don’t want to go to her house until I know she feels okay with what happened. I know he didn’t force her to do anything and he didn’t touch her, but what he did was still so inappropriate and it was his little cousin. Part of me wants to believe I’m just overreacting, so I can move on, but most of me is just so bothered by it. And now he regrets telling me. I love him so much and I know he would never do anything to make me feel uncomfortable and like he said his parents didn’t really stress the whole “keep your hands to yourself” thing like mine did, but I just can’t stop thinking about this. I just want to get over it and accept it and not be bothered by it, but I just want him to apologize to his cousin. He just says he wants to forget about it, but that’s not how that works. Am I asking too much in wanting him to confront her and apologize? The first time we talked about this was before Christmas and he’d agreed that it’d be in his best interest to confront her, but well Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> isn’t really an appropriate time to bring that up and we didn’t end up going to their house anyway, thank god, but I just think I need him and her to have closure, so that I can feel better and move on.