First off, I'm sorry your so sick. Bronchitis is brutal 'cause even when you stop coughing, your body is still exhausted and in a terrible funk. I hope you come through it as quickly as possible.
As for your fantasy, yup, I totally get it. I wonder alot if it would be better for me - not him - if I just cut loose. This is so hard, I'm 44 years old and for the last 6 years, I've dedicated myself to a man who teeters on the edge alot. Yeah, I think about it just as you do.
There's definitely something out of sinc in those of us who put ourselves through this. Most can't understand it and I don't blame them one little bit - from an outsiders perspective it doesn't make a damn bit of sense. We know what we would tell another woman who lives with as much pain as we do. We'd ask why the hell are you staying with this? Get out and have a life! But as a general rule, we aren't telling our friends/family the whole story so they don't know, but we listen to what they say and we question ourselves. I don't think that's a bad thing.
We have to think about all of the alternatives and know or at least think about what life would be if we choose to walk away. If we don't do that, then we live in isolation on an island where the rest of the world doesn't count. That can't be good. We do live in the world and we're entitled to everything it has to offer. Informed decisions are the only right ones. You are the only person who can decide if it makes sense to you - it's not an easy decision.
If you fall down 10 times, Stand up 11.