That was tough....I think you handled it well. YOu know that the OM calls so that was nothing new, but it triggered something in you today more than usual.
I was reading in someone's thread about a Plan A/Plan B thing. It almost sounds like what you are doing. I think it is trying2live's thread, and it was talked about in yoyo's. Anyway, maybe check it out. I can't remember the details but it is showing your true, wonderful self for a set period of time like what you have been doing (Plan A), and the after that set period of time you initialize Plan B which is letting her know that you don't want to live in an open marriage anymore and cut all contact with her except in dealings wiht the kids, and if there are things about the kids you have a "go between" talk to her. I'm really thinking this is a good plan for you. What do you think?