Oh dear
Lots of well meaning and really good advice but it's not so easy when you're living the situation is it? This is a heck of a lot to take in, so maybe break it down into steps.
Do you think you should be responsible for his care? Of course you love him, but can you see this isn't love? I'm sure that if the position was reversed, you wouldn't expect him to take responsibility for you, you wouldn't deliberately make his life hard - but he's doing just that to you. No matter how much we love someone, we should not, and must not, think that we are responsible for their actions. You may not realise it, but you are a strong woman. Look at his reaction to your talk this morning, if you don't do what he wants, he will let himself get ill. Can you see that this is blackmail? Do what I want or else..
But you can be strong. The more you show this strength, the more you are taking his power away from him and you have already started. Why should you live in fear of what he will do? Sweetheart, he is a coward, using his illness to exert power over his wife and children - and you have done NOTHING to deserve this. It's not ok, it's not right, but you can change it.
Go and see your gp, tell him/her everything you have told us. It will be in confidence, and you need to let someone know what's happening. Counselling could help you get the strength you need to stand up to his bullying, for that's what it is. Do you want to spend the next ten, twenty, thirty years living like this? Because it will only get worse, and your children need you more than he does. You aren't walking away, you are giving him the chance to do the right thing.
Be strong x