Spoon,

Stuff to ask yourself:

Do you both improve each other's lives? You certainly have a burden taking care of Michelle when she's not well. Is she also helping you out when she's well?

How comfortable are you talking about stuff on a level playing field when you're both in a sane state of mind?

Do you communicate, how do you work out problems or do you just let stuff stew? Studies of marriages have found that the ones that last tend to be partners who deal with shit. It doesn't matter if they get into epic fights (make-up sex afterwards for bonus points) or calmly work shit out. What matters is that they work through it.