Missing my previous ex after a toxic relationship

After my first ex and I broke up, I was extremely heartbroken and depressed. People that I thought were my friends decided not to be there for me in favor of partying and doing other things. So, I was completely alone and heartbroken which resulted in major anxiety and losing nearly ten pounds from not eating. After a month of this, I met a guy who completely turned my mood around. We became friends and then friends with benefits, and then more. I nearly forgot about my ex.

Then, the two of us started fighting and eventually broke up. We remained best friends, but continued to fight. These fights were not small fights. They often resulted in screaming, sobbing, and kicking each other out of our lives only to forgive each other in no more than a week. Looking back, our relationship AND friendship was extremely toxic and emotionally abusive.

But now, I keep thinking about the guy I dated before this toxic relationship. I can't stop thinking about how good it was, how incredible he treated me, and how much love he had for me. I don't even know if i'll ever find anyone who loved me as much as he did. We broke up because of long distance issues, but I was so angry and mean to him when I broke up with him and it sucks that it took an toxic relationship for me to realize what a great guy he was. We're on good terms now but I feel like i let a really good thing go, only to suffer a year of emotional abuse.

How do I find my peace? I just want to move on from both of them and be happy. I feel like I never got over my previous ex because 1) I jumped into the would-be toxic relationship too fast and 2) I can't stop thinking and crying about him now even though we broke up a while ago. I know we can't be together, and it makes me really sad. So how do i allow myself forgive, forget, and move on?