Welcome to SR Sadcat! I very very glad you found us.
Please take seriously what the others have said above. You can't fix this guy you can only destroy your own life.
Like you, I kept going back to my user; I was crazy in love with him. I did manage to leave him for good after a 5 year relationship. I didn't have any support (this was decades ago) but I left the Northern Hemisphere to put myself in a situation where it was difficult to contact him.
Please get as much support as you can: Alanon, friends/family, and Soberrecovery are great.
Let us know how you get on.