Hi Sleepie
This is a complex post. I think many many alcoholic and children of abuse and neglect have experienced the situation you describe. Over and over for me as I seem to pick the same kind of people. Alcoholics really do need enabling partners to continue their behavior unchecked. That or be completely alone....which is where things often end up.
So I will share what has worked for me. I allow myself to be treated the way I do (including enabling). I am not a victim anymore (I'm an adult and can walk away). I own my behavior and my reactions. My recovery is my responsibility and I do this for me. I look for support and validation from other alcoholics because they are the only ones who understand.
I'm so sorry you're stressed and frightened over health issues. I'm glad you are seeking medical help. I had cancer twice, 2 different cancers, and it was scary. My husband (who later died of cancer) did all he could but he was scared too and didn't really know what to do. And when I'm scared and anxious I get resentful and can lash out at those close to me.
Hang in there. Take care of you. You aren't married...if the relationship is toxic and un-fulfilling, leave.