Say NOthing about the relationship and divorce. When your wife brings it up, just listen. If something demands a response say you want to think about what she's said.
Good advice from Stumps but this is an area where you need to be careful. If you stonewall her, you're putting yourself in the role of her adversary, keeping her from getting what she wants. It's often more effective to use "relationship Judo" and lean into it, granting her what she asks for without friction.
If you're against her, that's what she will focus on. If you are with her, she'll have space to think about what she's doing and why.
WRT MC, go into it with low expectations. Unless both people are going into it ready to "do the work" and make some personal changes, it's not going to fix your marriage or prevent divorce. 95% of people go 3 years too late in a situation where one partner is motivated and the other is not. Usually the reluctant partner is going to be looking to (1) help the LBS find peace, (2) get validated by the therapist that the LBS was at fault, (3) point out your issues so that the therapist can help you fix them. None of that really moves your marriage forward.
The other risk is that the reluctant spouse is usually withholding and non-communicative. The MC may lead you to pour your heart out, which is generally not a good thing when your spouse is already trying to leave. Remember that just because you're in MC doesn't mean you should turn off your filter if your spouse is uncooperative. Focus on the communication skills aspects, active listening skills, etc. and spend the majority of the time data gathering.
It can be useful to meet with the MC alone, beforehand, to plan for the joint session, and to debrief 1:1 afterwards.
Acc
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015
