Is there a system that allows carers to get respite care? In the UK you can get a few hours a week, or a holiday (week off) now and then, and it's on a sliding scale. Just wondering if there was any way you can have a break because being a full-time carer is very hard, and that's without all the emotional stuff you are going through at the hands of your other half. It just even a few hours a week to do stuff for you can help a lot with mojo. I used to work in this field may years ago, and saw the desperation of those who needed it, and it is a proper need. Caring is one of the toughest jobs out there.

If you can't get respite, then I would make sure you get at least an hour a day to yourself. Go for that bath. If you're not eating, go get a sandwich and a coffee in a nice coffee shop. Go phone a friend for a natter - anything that means its 'you' time. I don't think you have an alternative, as you say, you're starting to feel dreadful. You will not be able to care if you do not look after yourself too.
You say that the house would fall apart without you - well, from my experience this rarely happens. Necessity takes over, and things get done. Sometimes people help out so much that the person being helped stops doing anything for themselves, and around we go. I do agree with trippin, let him do some things for himself. On the issue of shooting himself, I would think very hard about letting authorities know, it may be that he gets some help - this stuff is too much for just you to take on - too much for just one person whoever they are.

On the issue of your other half.. yes, he's been great with you when you were messed up in the past. But does that give him reason to be cruel now? I don't think two wrongs make a right, if you know what I mean. If it's dragging you down, it's ok to be fed up about it, no matter the history. Do you talk to him about it, or is it got to the stage that it's always going to turn into a fight?

Hugs.