I really feel for you. It’s so hard to keep going around in circles. I don’t think they mean to keep hurting you it’s what that stuff does to their brain, it turns them to selfish people and the most frustrating thing is they can’t see it or refuse to see the damage it does to everyone around them.
I sounded like you till I’d eventually had enough. You have to put yourself first.. do you really want to keep living like this? If he won’t get help then you need to protect your mental health. You’ll end up in some dark and lonely places otherwise. Have a break from the relationship see if time apart gets you some perspective maybe? The one think I’ve learnt the hard way is you cannot fix them, no amount of pleading will change them.. you can only work on you. You have one life so choose how you want to live it.
If a relationship is draining the life from you, you got to ask is it worth it? Only you know the answers but surround yourself with people who love you and make you the best version of you x