Oldest dc is nearly 12 and has her own phone. Ex has started texting her when dc are with me asking if he can 'pop by' to drop off snacks, toys, etc when we are all home.
Today we are lounging around the house and he sends her a text saying he has some sweets and he'll be round in a minute and she and her brother should get dressed and come outside to get them. I called him and said its not ok to do this and that I'm not comfortable with it. He has now kicked off saying he wasn't trying to come in and that he shouldn't need permission to drop things off to dc at the front of the house.
I know ianbu but I'm struggling to articulate why. Background is ex is extremely reactive, controlling and constantly pushing boundaries. Dc don't particularly like seeing him as his mood can change so suddenly.