Hey, firstly sorry you are going through this. I can only speak from experience, attending family groups and reading, there is nothing you can do to help him get better. Showing more or less commitment to a relationship won’t change anything as the addiction is in him and only he can change that.
Don’t know if you’ve ever heard of the 3 c’s for people affected by a loved ones addiction, but it has helped me lots. You didn’t cause it, you can’t cure it and you can’t control it. It’s so easy to take blame or feel we aren’t doing enough, I’ve been there, but honestly there is nothing you can do apart from if you decide to stay in the relationship be supportive but always put yourself first x