Oh lord I feel for you RyVeeta what an awful situation :( 
You have so much guilt weighing on you, I can almost see it, you burdened with a hundred bags of wet sand pulling you down so far you're crawling along.
This is no way to live. Actually, it's no way to love either.
I am severely disabled and with two of my family dead from the same condition, i am very scared for my little boy and what he would do without me. I live with this daily. My husband increased his abuse as I got iller. He doesn't know where DS and me are now. I am crippled, literally, bed bound mostly and in incredible pain amongst other symptoms. About half the time I wish I was dead, no one should have to live this hell. The other half of the time, I am terrified I will die. So not just sailing merrily through the whole 'becoming disabled, no family to care or help' thang.
I'm hoping telling you this will help add some credibility to what I'm going to say. Rather than being a dribble of misery!
So... I feel well qualified to say, your husband is a selfish manipulative cruel and revolting arse.
He has made you into his servant, well, his slave really, since he doesn't pay you for the abuse he gives out. He makes you pay though, every moment of every day it sounds like.
What he is doing has nothing to do with illness or disability. It has everything to do with his vileness and pathetic ness.
It makes me angry that he dares to use illness or disability as an excuse to be like this. Take it from me, it's not. At all. Do you think this is the way every ill person behaves? Its really really not.
I am by NO MEANS perfect, and sorry if it sounds like I'm putting myself on a pedestal here... I think that's the point though, I'm definitely not the image of the sainted ever-patient ill person. I'm grumpy, pissed off and over sensitive. I'm also depressed and struggling with that, and am getting help.
And yet still, I can't relate to any of the way he behaves... Even an impatient misery like me :)
Of course everyone has bad days, and being in pain makes it hard to think about anything else sometimes, but not the way he behaves. That's not from pain, that's from him.
He is using your kindness and sympathy. He is using the excuse of 'being poorly' to rule you, to torture you and to break you. And I'm worried it's almost worked, and so glad there is a flicker of your spirit left - it's amazing and brilliant of you to have this tiny spark left. Please don't let it go out. You need it
You deserve to be free of this terrible man. You need to be free, as no one can suffer through so many years of this and hope to come out unscathed.
I don't think you are selfish, or being unkind to the poorly man. I also don't think what you're living with as trivial. The opposite in fact. 
Please don't feel guilty because he's an 'invalid', or fret over how will he manage without you. You need to start caring for and loving yourself.
You're the one in the most pain in that house, not him.