It made me so sad to read your post. I can feel the terror in your words and I remember it so well. A little different because it was my boyfriend with the problem, but everything you say was how I felt at the time. I truly think it almost killed me. What saved me was that every time I started to spiral I just asked myself "what do I need right now?" and instead of doing what he needed I did what I needed. It took awhile but eventually it became habitual and gave me back some strength. I hope you find peace soon, I am so sorry you have to suffer like this.
As for prison, when my ex was in prison, life was so much better. I knew where he was, he was sober and he was working on himself. Sometimes what you fear can actually be a blessing in disguise.