Just to add what really helped me was for me to learn about alcoholism.
I came from generations of alcoholism, married an alcoholic but I did not understand how it works.
This was a real game changer and help to me. You mention he is very "complex", I politely say that it isn't, he is a bog standard alcoholic. They all do the same stuff. Once I saw this, I couldn't unsee it and it helped me enormously.