the thing that stood out the most is this: "he'll say he's worked so hard his whole life and he just needs to take time off. "

If that's what he says, then it's no longer about disability and not being able to work but about him feeling he deserves this time off. Which on the one hand I can understand, many of us would feel that way but unfortunately it's at the expense of you. Your health, mentally is being sacrificed for him and if it's not because he CAN'T work, it's a decision he's making now not something he has to do.

It would bother me to no end also.

And I don't mean to paint him in a dark light entirely either, I am sure there are issues at hand he is dealing with but I just can't help but think there may be a selfish factor here on his part.

It is good you're looking at things the way you are and to be honest, I dont' really have any solid advice but to say you need to seriously assess whether your goals in life have diverged at this point. You want a family and a stable life. he wants freedom and a long vacation. I think a few months off in most cases is enough but 3 yrs?