Dear Jawn, I am so sorry, and I know there are no words to say when one feels so sad and my heart goes out to you, I echo what Nicolette and others have said, that some things- ptsd, pride, stubborness, addictions- so many things, can destroy relationships that otherwise may have succeeded without it.
With all due respect to Superjen (and dear SJ I agree, one comment should not 'cause' such a thing- you are speaking from a 'healthy viewpoint)- but it sounds as if your wife is so ill for lack of a better term that all it took was one comment for her to focus on and have her invalidate anything that might have been positive. But no one can also live within a relationship equivalent to a house of cards- at least in-so-far as it will continue to cause great pain without progress. I think she is also being honest as regards saying she is numb in her feelings for everyone. At those times no one can love another, and that may last for years or decades or perhaps never fully change.
One minute at a time jawn, and please allow us to offer you lots of hugs and care, I am so sorry this is so heartbreaking and if I could do something that you wouldn't have to feel this way I would. It is a terrible illness, no one gains.