Good luck working your way through your difficulties. The main thing is to know what choices you have and what options you don't have. The option of him getting therapy and substance rehab and modifying his behavior is not on the table. He is crystal clear in what he proposes to offer you. His behavior will remain as it has been for a long time. You can coexist with that or separate from him. Those are your choices. It's your call.

After a certain age, courts and police really won't do much to force a child to be with a parent the child doesn't want to be around, especially if substance abuse is going on. A man as self-centered and dysfunctional as your husband is unlikely to care very much about devoting time to spend with his children after a marriage ends. Were you to divorce him, your husband would be quite content to leave managing the kids entirely in your hands. He sees them now because he can't avoid seeing them. So it's a stretch for you to think, "My daughter is better off with me staying married because shared custody would be hard on her." That's you straining your brain to rationalize preserving the status quo.

Continue the marriage, if that's what you want to do. It's entirely your right to choose that option.