The others are right, you can't say anything to him even about your D's. I know your're angry, but bring it here. It could be that your anger is making him feel more guilty. That really isn't good b/c the guiltier he feels the less likely he is to see his D's. I think you need to stop comparing what you do for his son's with what he does. He isn't you and he's insane. Be you kind sweet self (as always) for the boys and the others in your life. Do not expect anything from him. It will make you crazy and not help your sitch at all.
Have a great time at you D's party and a wonderful Easter.
