Is my (21F) ex (27M) redeemable? Should I have broken up with him?

Hey everyone, I broke up with my (ex)bf about 2 months ago. We had been together for about 9 months. Recently I’ve been struggling with my feelings of still being in love with him and wondering if he is redeemable, if it would be stupid to try again.

At the very beginning of our relationship (May 2019) he lived out of state and I was visiting him with my best friend. On the last night of the trip, his best friend sexually assaulted my best friend in her sleep.

We pressed charges and I cut his friend out of my life completely. Since then it’s been a struggle, because my BF had a hard time processing what his friend did.

In the beginning I didn’t know how to feel about them still being friends, I mean he was mad at his friend and told him how wrong it was. He definitely called him out, but the friendship continued. After three months I realized that was a hard boundary for me and I didn’t feel comfortable being in a relationship with someone who remained friends with someone who assaulted my best friend. I finally realized it was ok for that to be a boundary for me. So we talked about it and it was very emotional but he agreed to cut his friend off. I told him I’d give him more time because I wanted to be empathetic and understand that he’d be losing his best friend of 8 years.

Unfortunately it never happened. He did distance himself for a while but he never cut him off, and after 6ish months (March 2020) they were still friends. We started fighting about it on and off because I didn’t feel listened to or validated, I started feeling kinda like the crazy selfish one. Whatever. He eventually started lying about them talking and hanging out because he didn’t wanna upset me and he still wasn’t ready to cut him off. There were some other contributing factors to the breakup, but they were things I was definitely willing to work on with him. But this at the time felt like a big breech of trust for me. I felt my boundaries were ignored and like I just couldn’t trust him emotionally anymore. I didn’t feel respected.

So I broke up with him, he was really upset but accepted it. His reasoning was that it was his best friend of so long, and the idea of cutting him off was very painful. His friend is also (in my opinion) a selfish narcissist who is very manipulative and charming, good at getting people to stay in his life who don’t deserve his treatment. I don’t think my ex saw that, but it was very clear to me.

For the next month we were in contact on and off and he told me I was in the right and he was so sorry for everything. He recognized what he did wrong. He also has officially cut his friend off forever now. He wants to try one more time and show me that I can trust him.

My head is a mess. I just need to know if this is worth another shot. We have such similar life goals and I really love him and I know he feels I’m the love of his life. I’m just confused. Can this be fixed? Am I being stupid ? I want to try again so bad. But I don’t want to be stupid. Pls help.

TL;DR BF broke my trust and I can’t tell if it’s worth another shot.