No Code's idea is a good one. Keep in mind, if you file jointly, you'll probably both be better off, and, if you don't, he has more to lose. So, I'd come up with a plan to file jointly that makes you better off than if you file separately. If he doesn't like it, he'll be the bigger loser.
As for what happens next year, have it specified in the D. All this is purely business, don't let him play you emotionally.
