How to get over ex bestfriend

I was friends with him for about 3 years. We did everything together, he knew me more than I knew myself some days.
He started doing some things that were really messed up. I don’t want to go into specifics of what happened in case anyone were to ever find this lol. But it was all pretty bad to the point that I couldn’t trust being friends with him anymore. So our friendship ended. After that I found out that he’s been going around talking badly about me and trying to make random people hate me.
I don’t understand why, I know that I had my faults, but I just don’t get why he could hate me so much.
I truly miss him everyday. I wish that our friendship didn’t have to end, but also after the things he did i know it had to.
Sometimes I want to reach out, but after finding out what he’s been saying about me I know I shouldn’t.
Does anyone have any advice on how to get over a friendship? It’s been almost a year now and I just am lost on how to get past it.