I'm sorry you are having a hard time of it at the moment. Not allowing things to escalate is difficult. Things will naturally escalate when you have two people who are hurting and confused. Hurt people hurt people. When these convo's start all the things we've been holding in, our hurt, our resentment, our feelings of rejection and our confusion comes pouring out of us. And by us I mean you, me, your W, and my H. We are all hurt, resentful, feeling rejected and most of all, damn, we are all so very very confused.
I avoid all R convos for this very reason, but so does my H, so it isn't too difficult for me. The alternative is those two people put up emotional barriers and use avoidance as a strategy. In my sitch there is a complicit contract that we will avoid all R conversations, keep our discussions short and to the point and try not to be in the same room for longer than necessary. This alternative also s*cks because beneath the façade of emotional detachment, is still two hurt people who are better at hiding it. And it doesn't change the fact that hurt people hurt people. It is just more under the radar. But, I agree that this alternative at least has as its objective self preservation. Eventually the pretense of emotional detachment becomes actual emotional detachment - and it is only then that they lose the power to hurt us and in turn, we will not feel that need to hurt them. So, I understand your struggle. I would suggest avoiding the R talks (but you know this), focusing on your kids (as you are doing) and your own GAL. Eventually you wont have to try to be emotionally detached. You just will be.
You ask whether your W bringing OM to the house is a deal breaker for you. Do you have an expectation that she will not? Because she will - she will want to start sharing her life with him as soon as she can. It is the fantasy of a new life and that new life includes OM. It may all fall down in a heap around her later, but right now, her fantasy is still int act. Don't ask yourself now if it is a deal breaker, because your views will change depending on how far down your journey you are when it happens. What I have put up with, the many lines I've drawn in the sand, then, broken and weeping. stepped over, would astound you. And I am not alone. Those of us who still hold out hope for our M have all stepped over those same lines.
What you can and should control is what relationship this OM (and any other future OM) will have with your children and this must be articulated and agreed between the two of you. Trust me, she is just as afraid of you bringing OW into your children's lives. The maternal instinct is a strong one, even in those in the middle of a fog, and the very thought of another woman in her children's lives keeps her up at night.
