BND... For now, I would take it as a good thing. Look, he has opened up and shared with you some honest feelings about the marriage. Yes, these men are in MLC, they have some sort of depression...but there is a kernel of truth in what they are experiencing ( except it then gets distorted/delusional/wacky).
I'd validate his feelings and go have some fun! You need to build up the positives first.
Ultimately he will have to learn how to handle his mixed feelings ( and so will you, because there will be bad days). But it's easier to get through the yuck stuff when overall, there is spark ( and hope ) in the air.