Puppy, Thank you so much. Is what I'm planning on saying, what I should be saying? "Your relationship with this OW is hurting me and the rest of the family. When your done with her and agree to NC, we can talk" then I plan on walking away, and not waiting for his response.
I think that's perfect. Just be sure that he also knows that your patience isn't without its limits, and that -- while you are waiting -- you WON'T wait forever.