I'm sorry to hear the situation you are in. I hope that the responses on here have given you some support and some ways to get through your days.
It is hard. And even having been in a similar situation to you for 18 months, I still don't know what I can say to you to make it easier. But here are some things I have learned...
You can't fix him. No matter how hard you love him. Firstly he will need to want to do that. And even once the action is taken to seek help and start improving, it still takes time. You just need to be patient while he does.
Don't doubt yourself. As hard as it is, try not to take things personally. If what you are doing is what you believe is right because you love and care for him, then do it. It may not be perceived that way. I was told that he may not react to my actions right away, but he would have heard what I said, and remember what I did.
Find support. Medical, professional, personal. You'll need it. As much as he needs love and support, if you are going to get through this, and you are going to fight to support him, you need it just as much. As much as this is his struggle, it still affects you. And it is tiring. So find people to help you, so you can stay strong for the journey.
A friend of mine told me that, he is just on the other side of a big solid wall. But that wall will come down over time. And you need to be on the other side when it does. I too, was worried that after the walls came down, that he'd still feel that he didn't love me. Or still continue to believe that I didn't love him. But I had to trust that, those decades of love, would be what would keep us together once the walls did come down.
There is a YouTube video, called Living with a black dog. It is specifically for partners and carers:
And the last words in the video say...'always hold onto hope'
My husband tells me that I am naive sometimes, and that I sound like I live in a fairy tale. I know for sure this isn't a fairy tale. But I have to believe that hope is the one thing that got me through each day, and continues to get me through.