I had loads of crap with my ex at one point. He was being ok one day then another time would start arguments for no reason and I couldn't work out what was going on, until I realsied the only time he started was when I was outside his house dropping off or picking up my kids, cos his missus was watching! I have no interest in going anywhere near him, but he tries to make her think I still want him in order to keep her feeling insecure (tried the same on me when we were married) so everytime he started, I just drove off so he started ringing and I hung up, then he even wrote me a really nasty letter, so I threatened him with a non-mol order. Peace of a sort has reigned ever since, although his woman does try to stir shit between him and the kids. Anyway, my advice, is ignore him. A person can only make you angry if you allow them to. You have the power not to listen. You have a right to make sure your son is ok, after plans have been changed. If he or his GF get pissy, ignore them and keep any evidence for court, incase it ever gets that far.