Uh well they are YOUR kids too the last time I checked. I've seen instances where you can get it legally written out where no one new is to be introduced to the children after a period of time.
You can't control her, true. But you can prevent the children from being involved. Get to a counselor and get their opinion. Have your W attend too because this is about the kids, not the both of you.
Let's put it this way. Is this how you want your kids believing this is the way a M should go? Do you want them to get the impression that Dad thinks it's okay for another man to take their mommy away right in front of them?
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.