Depression is a common phase during piecing. I think it's one of the series of steps that we all have to go through.
Honestly, you can't make him do anything about it. And pushing the subject is just going to make him more grumpy about it. He'll have to figure it out for himself.
That doesn't mean you can't be supportive. You can reiterate that this is your choice, you are happy, you can make your own decisions, etc. Be kind, be loving, do things that appeal to his love languages. If this is related to part of the healing process, he will come out of it when it's time.
