One of the biggest misconceptions is that once the OP is out of the picture that the marriage will be magically saved. The affair is just a symptom of the problem.
Blue it feels like you are trying to force things right now and that is only going to push him away. I really don’t think you should be in MC right now. You need to give him time and space to sort his stuff out. Stop worrying about what works and what doesn’t and stick to Sandis 37 rules.
I really think you need to understand the timeline here. This is going to take many months if not years to play out. There is absolutely nothing you can do until he is ready to recommit to the marriage. For people who are control freaks that can be a bitter pill to swallow.