How to move on & let go

So me & my ex( I broke up with him on Friday because I need to focus on myself) were together for 1 year & 8 months. We’ve been through ALOT. there were times where we’d both been toxic & hurt each other but we stayed because our feelings toward each other were so strong. In dec-Jan we were going through some things & we had been arguing a lot. He compared me to his ex who he was with for 3 years in a argument and since then I became sooo insecure. I was hurt & I felt betrayed. He told me that he wish he never said that to me he didn’t mean he just wanted to hurt me because of something’s I’ve said to him as well in the argument. Till this day he stands by it and tells me he was childish & he learned from that and he has never said the same thing again. I feel like since then he’s hurt my ego & I have a veryy high one so I felt shattered. I tried letting it go but it’s like it made the relationship worse. Aside from feeling insecure here & there i stopped trusting him, id accuse him of still being in love with her and cheating on me and not loving me. I’ve never had proof of him ever talking to her or anything like that but since the comparison it’s like it haunts me. There are times where I don’t even think about it I feel so secure & beautiful then there are times where it haunts to the point I randomly start accusing him & hurt people hurt people so there were times I’ve been so disrespectful to him because I looked at it as well you hurt me , you didn’t respect me when you compared me to ur ex and made her seem better than me so why do I need to respect you. I left because I felt like I need to get rid of all these insecurities that still haunt me sometimes from 7 months ago!!! I literally find myself randomly checking her page still comparing myself to her and feeling so insecure all over again. He feels bad he even told him mom & aunts what he’s done and they even told him he was very wrong and me being insecure was definitely gonna be the outcome what did he expect. I don’t want to breakup forever but I feel like what happened 7 months ago made me fall out of love. Even tho I may love him.. I’m not in love with him anymore and I feel like our relationship has become so TOXIC & unhealthy because of that. He regrets it , I can tell but it’s already happened. I just need some help on how to move on and stop letting it run up on me. He tells me I’m beautiful & have nothing to worry about but sometimes I can’t help myself but rethink of the past. It didn’t even affect me this much around the time it actually was said. Now it’s like it’s affecting me the most. It makes me anxious AF & since then I been overthinking everythingggg. He says I can’t enjoy the moment cause I’m always thinking so deeply. I want to learn how to let go because tbh there were times I’ve said some bad things to hurt him to out of anger but I just want to fix this (if there’s even a possibility) I’ve been randomly feeling so negative since July & just so down and on & off depressed. I’ve been insecure & doubting myself. I just want to let go of all of these feelings , I want to forgive him wholeheartedly cause he has forgiven me for things I’ve said to him & I just want to start over and Fresh and work on pursuing a healthy relationship. Even when we break up it’s like we can’t leave each other alone it’s really really hard.