My boyfriend used to hook up with my friend and I feel insecure now.

I (23F) have been with my boyfriend (25M) for just over two months and he?s absolutely amazing. At a party a few nights ago, I introduced my boyfriend to my friends who hadn?t met him before and one of them recognized him and went for a hug. I asked how they knew each other and she responded saying they were ?friends? but it was pretty obvious it was more than that.
I figured that I would ask my boyfriend about that later but I couldn?t stop thinking about whatever it was between them and my boyfriend noticed and pulled me aside during the party and asked if I was okay. I told him that I had an uneasy feeling about him and my friend so we left the party and went back to his place where he told me everything. He met her at a club about two years ago and they hooked up that night and they kept on hooking up except for a seven month stretch when he was in a relationship with someone else. My friend wanted them to be in a relationship and he said he only wanted to hook up and she wasn?t happy about that but she continued hooking up with him, even initiating and asking him to meet up most of the time. The worst part is she was in a relationship during the times they were hooking up and nobody including my boyfriend knew she was cheating. The last time they hooked up was three days before our first date and he declined her asking to meet after that.
He offered to show me the texts between them and I?m not proud of it but I did take him up on the offer and looked through their conversation and everything he says is true. He was faithful to his ex and he?s been faithful to me but I still feel really insecure. Part of it has to do with looks I guess since my friend is absolutely stunning while I?m a little chubby and my boyfriend is really handsome and in great shape. He even got a voice note from her this morning where she was crying and saying he deserves better and asking what I have that she doesn?t and why I became his girlfriend so quickly while she waited two years for nothing.
I?m not breaking up with my boyfriend over this whole thing since he quite literally did nothing wrong but I feel insecure now, about my looks and in our relationship. What should I do?
TDLR: found out my boyfriend hooked up with my friend over a span of two years before we got together, feel insecure now


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