Welcome to you Yurt. I relate to so much of your story!! My XAH was also disabled; and with all that unstructured time the alcoholism gradually ramped up. It took me years to recognize, I knew he was acting different; but attributed it to his disability. It also made the decision to leave a torturous one. Oh the guilt!!!! We also had teenage children whose lives were greatly affected. There were emotional struggles for sure; but they are both living happy and successful lives!
I can't imagine what my life would be like if I had stayed. I can't tell you what is right for you. I know there were many things that I valued that I thought would be "gone forever" if I left.... the main thing for me was the beautiful house we had built together. But I couldn't take the pain anymore; so I left. I have been amazed to discover that letting go truly did open up opportunities for a better life (and home) than I could have ever imagined!