oh Finch I am so sorry that you have had to go through this. I wish I had something truly useful to say to you on this. Just remember you can be supportive without having to fix the situation and you can take care of your needs without guilt.
I find that when I take care of my needs I can be supportive of someone I love that is in great pain, without feeling the need to make them different. But the only person I can speak for is me, and the only person I can change is me. So that's where I go. Things often work out if we stop picking at them. Be your kind loving self but take care of you. Just like if he were in the hospital, you would still have to eat, sleep, have some time away from the hospital it's the same here I think. Be a good communicator and state your support in clear terms with kindness and tact. I know you are hurting. I suppose if you want to cut your losses you could but that would ultimately be your choice. I hope this helps. Hang in there.