There are a lot of red flags that would indicate that your H is or has been having an affair. I wouldn't even bother with MC at this point since he seems unwilling to work on any part of the relationship.
First of all, take care of yourself. Eat, sleep, exercise, charge your battery. You don't mention children, so I assume you don't have any. That might make things easier; kids make things awfully tough.
What do you want? What changes do you need in your relationship to get your wants and needs met?
If you've decided to move out, why wait until Christmas? Living like you are for 2 1/2 months seems like hell to me.
