I feel very sorry for you, carrying this pain around for 30 years. I don't think most women would keep their child's father away from their daughter over cheating, especially not for years and years. The price you're paying is not for civility, IMO. It is the price of carrying a grudge. Holding a grudge only hurts you, not the person who betrayed you. It's like drinking poison and expecting the other person to die, as they say. Is there a counsellor or therapist that you could talk to about this?