No go on the bedroom thing for now. Either be there, or don't, but that separate bedroom thing seldom ends well IMHO. What has been working for YOU is that he has had more positive moments with the R when you and he have good times together, and when you went on vacation by yourself he got worried and scared.
So - why not just schedule the MC and leave off R discussions until then - when you're with him, continue to show him the positive you that he will be missing - take one meeting with an attorney to find out your rights about the house etc. - start squirreling away a secret stash of cash for emergencies - take a road trip one weekend to visit a DB friend - let him wonder
And most of all, decide what you really want. He's like a drug addict right now, he needs his "fix". He won't quit until the costs of continuing it are more than the high. If you had plenty of money, would you still be there? Can you move in with family or friends and still pay your share of the mortgage? Can you file and force a sale of the house? Get legal advice before you do anything.
Me, I'M tired of him! But if you still want him, stick to your boundaries and start letting him wonder about you again.
