perhaps he pushed a codependent button. you have been the one who rushes to his aid, but the role was reversed? you don't feel like you "should" be consoled, you are "supposed" to be the strong one....? any number of things, combined with your dismay over what has happened in your young marriage, could have put those feelings into play.
and i don't think it's at all silly to be sad about your first christmas. not at all. it's called grief.
you sound like a smart and strong woman, doing what is right. sounds like he is on right track as well, for now, and i wish you the best