How I can (22M) get past my GF’s (25F) past relationships?

TL;DR: Just wondering if anyone has any advice to help me overcome my negative thoughts/feelings about my girlfriends past physical and emotional relationships.

Here’s a bit of context because that’s always helpful.

My girlfriend hasn’t had any one night stands or anything that would even be remotely considered promiscuous, however, she has been in 3 past serious relationships. These relationships have lasted around 1-2 years each with another lasting closer to three years. All these relationships have apparently been both physical/sexual but also quite emotional. She started dating right before she graduated high school and has more or less been in a relationship since then with breaks lasting at most 7 months. Additionally we’ve been dating for almost two years now.

My story is a bit different I guess. I’ve been in 4ish relationships (depends on how you label them) but none of them very serious lasting from anywhere to a couple of weeks to several months. However these relationships weren’t physical/sexual or really emotional either. We would talk and spend time together but I would never really open up, in every meaning of the word. I didn’t share my deepest thoughts or fears or emotions. We never did anything physical beyond some light touching. As cliche as it sounds I would try to picture myself decades later with them but I never could. And when that happened I would just cut things off.

I met my now girlfriend during a summer break from college. We were both working at the same restaurant and we started talking. That talking turned into flirting and after a couple months we started dating. And if I’m being honest I like her a lot. At this point it’s pretty serious and I’ve opened up/committed. I’m emotional with her and physical/sexual. She knows me more and better than anyone else.

Her ex’s aren’t brought up often. She’ll sometimes say something about them or her friends will ask if her parents like me more. You know, off handed comments more than anything else. However sometimes when its brought up my mood definitely shifts. I get more distant and less talkative and this last time I didn’t even want to hold her hand.

I have tried to know a bit more about her past so maybe I could resolve my feelings but I don’t like talking about it. Apparently she wasn’t very happy in any of the relationships after the honeymoon phase but waited a while before ending things. She said she never got very physical but I’m not sure I believe that since her friends have a “nickname” for her and she’s pretty good at something. I get that leaving relationships is hard and it’s tough to say no or disappoint but I’d be lying if I said it didn’t irritate me.

And it’s not just the whole sex thing. I’ve thought about and while that’s a part, I feel as if she’s given everything away. Sure she chooses me now but she chose them before, she’s physical with me but she was with them. She’s shares with me her emotions, her thoughts, feelings, fears, vulnerabilities, the things that make happy; but she shared them with her ex’s too. I have her heart now but other’s had it in the past. Call me selfish I guess but I don’t have anything of hers that is new. Everything she’s shared or done or given to me she’s also shared/given/done with someone else. There isn’t any meaningful parts or firsts that only I have. And again this irritates me.

I don’t lack self confidence, I’m quite a bit better than all her ex’s (maybe that’s arrogant but it’s better than alternative emotions). She says she’ll follow me anywhere and I believe her. No relationship is perfect but I struggle with this more than anything else. But I like her a lot, would like it to work.

Sorry, I know this long/a lot but I’d appreciate any thoughts, advice, and help.