You have been with him for a long time I imagine is part of the reason. You love him, you want him to be ok. You are his spouse, its in our vows to support through sickness and in health.
Being married is an identity. Your identity is "Mrs X'. This is one of the hardest parts of divorce, to find out who we are when we are no longer 'Mrs. X'.
I think you have a lot to learn about alcoholism - it sounds like you don't fully understand the disease. Its not personal, really, its not. He didn't choose it, no one would. You are also imposing logic on a disease whose very existence is illogical.
You are also doing a lot of what we call "future tripping". Future tripping is the road to hell. The fact is no one knows what will happen in the future. Here is what we do know in the present. Your husband is an alcoholic who is not seeking recovery. He has told you to move on. He has told you he is unsure whether he will ever stop drinking. Today what are your thoughts on that? Do you wish to live with his active alcoholism? Do you want your life to continue to be chaos and unmanageable?
You are spinning your wheels over the future - the what ifs. What if he stops, what if he recovers, what if he wants to try again?
Well what if he never stops, never recovers and never wants to come home. How long will you wait to see "what if" he does?
Live in the present and proceed with what you know. Al Anon does not require you contribute, you don't have to say a word. You will find people who are going through exactly what you are. You can work the steps (if you choose) to overcome this. Highly recommend it.