One of the first lessons I learned here is the 3 C's.
I didn't cause it.
I can't control it.
I can't cure it.
I just need something to change
This is truth, you need something to change. You've tried for years to change him and that didn't work. So, the only thing left to change is you.
He is showing you the real him. Believe it. It's who he really is. Dr Jekyll and Mr Hyde are a package deal. No matter how nice he is at times he is also Mr Hyde.
I know this is hard, I've been in a similar place with my xwife. But at some point I had to change or else. I had to accept that my marriage and my relationship were toxic to me. It isn't about punishment or revenge, it's about survival.
You are worth it.
Your friend,