IMO, I wouldn't do anything about the D, if he wants it he has to do the work & also he has to pay for it! If your proceed you might end up paying & you don't want that.
If he starts the D, get a good L, tell him what you want & stick to it. Your H may back down, it's sound like he doesn't know what he wants.
I'm sorry you are so depressed, but I know exactly how you feel. I was feeling the same way today b/c of the weather & the time of year. I also am happy on the outside & that is what I show people but then fall apart later.