Background: Ex, very brief fling, split up before DS was born. His family are abusive and controlling which have left him with severe issues and learned helplessness. He doesn't pay maintenance, makes no effort to contribute to his son and only wants to see him on his terms. He gets very moody when he doesn't get his way.
Ex wants to take DS to see his nan as she's very ill and hasn't seen DS. I'm completely okay with that! But he wants to go in December. I don't have a car and he lives 3 hours away, so I would have to go when I can use my parents car, so that leaves the weekend. Most weekends in December I already have family things planned. One weekend I'm away. DS is 12 weeks and I don't trust my ex with him without me there as he is irresponsible.
I told him I would try to rearrange things but can't promise, he immediately said I was being a bitch and "clearly busy sleeping with another man", he then proceeded to make digs about my "new boyfriend" and just generally became abusive.
He's since apologised but still claims IABU about this.