My ex husband and I coparent 50/50 (1 week with me, next with him). He met a new GF in May through OLD. He introduced her to our children, 18,16 and 14 in July and they met her again at the start of August. On returning from a holiday with me at the end of August, the children returned to his house to find she had moved in her belongings and had set up her home office in the kitchen. They were upset that she was staying overnight and felt uncomfortable entering the kitchen. They tried to discuss the situation with dad saying they felt uncomfortable and didn’t like it because they didn’t know her well enough. New GF took offence, cried and argued with their dad and took her stuff and left. He blamed the children for making them split up. He stopped talking to our 16 year old saying she was rude to new GF and needed to apologise, which she did the next time she visited, though denied being rude. Over the next few weeks there were lots of arguments with the children complaining to dad that they felt uncomfortable and not wanting new GF around. She moved her stuff in/out three times in one week. Each time she left in tears complaining the children were ruining everything. The children asked dad to slow down with introducing new GF. He agreed to scale it back to no sleep overs when the kids were there. The agreement was broken within 2 days, sparking more rows. Our eldest returned home to find them in bed together and she knocked on the bedroom door asking dad for a chat. She asked why he had broken the agreement. He said it was his house and he could. Daughter called me and asked to come to mine overnight instead, which she did. She rang dad the next day to discuss. New GF took the phone and started yelling down the phone. This went on a while. Daughter asked to speak only to dad, which wasn’t facilitated. Daughter hung up. She returned to dads house the next day for some belongings. She has since received a text message from dad (although the language used is not what my ex would normally write, so I would imagine GF has written it) to say she can move in with me if she’s not prepared to accept the relationship. Both the older children are miserable. Youngest is not bothered. The children want the coparenting with dad to continue, but are not ready to accept the fast pace of the new relationship. The GF has upset the older two children over a lot of things, including intercepting all their calls to dad, replacing a photo of them on his mobile home screen with a photo of herself, interrupting their conversations with dad and telling them they are rude, disgraceful and immature. The children have decided they don’t like her at all. She told our16 year old that her goal was to move in permanently by xmas. Any helpful suggestions on how to navigate this? I have asked my ex for a chat about it but he has refused.