Is it ADD or sexist role stereotyping?

My husband and I fight all the time about his refusal to do what needs doing in the house. I need help!!

For background, I married a sweet man who would do anything for me. He drove me to work and home while we were dating (2 60-mile trips each day). He is gentle and sweet and did not come across to me as a male chauvinist pig who expected the woman to do all the work.

When we got married, I saw a different side of him. He stopped working and I had to explain "My husband chooses not to work" when people asked me what he did. But he still didn't do any housework, even such basic things as dishes and laundry. I was working from 9 am-10 pm and still had to fit all the household stuff around that.

Now he's medicated and working, and I am a full-time student (16 credits this semester). I have mobility issues and have trouble walking. But he refuses to do anything. I do not see the distraction, the "I meant to but I forgot." This is just flat out refusal. "Honey, the dog needs to go out before you go to bed" and he just looks at me and goes to bed without saying anything, or doing the simple task I had asked him. I hate walking the dog! My balance is so poor that the dog can pull me over and once I've fallen it's incredibly hard to get up, and he knew that when we got the dog. He will say I'll do it tomorrow but it needs to be done NOW! It does not feel like ADD, it feels like he doesn't love me and doesn't care how much harder it is for me to do things than for him.

Is this just ADD or rampant sexism? When I talk to him he says I don't think I should have to do it all. But when you marry someone with a lifelong disability, shouldn't you expect to do more than your normal "share"? Shouldn't the person best physically equipped to do a task do it?

This is a deal-breaker for me. It is much easier to do the housework for one person than for 2, and I'm thinking fond thoughts of the single life. If I wasn't there, he'd have to walk the dog. Is there a way to make him see how unfair this all is, or should I just suck up the pain and fear and lack of sleep and do everything he does not think he should have to do?