People can say things that are awful. I have been guilty of saying things that I know would hurt my partner. It's not right and it's natural to feel hurt. If you think that you can't discuss this without "one upping" her statement perhaps write her a letter and tell her how you feel. Perhaps couples counseling and individual counseling is necessary.

Every relationship has it's stresses and yes being with a person that is diagnosed may have different issues, but I think most couples could benefit from counseling. Does you wife also have a good support network of her own? Perhaps she has been feeling overwhelmed.