I split from my ex-h 6 years ago. We have 50:50 parallel-parenting of 3 children. D1 is 18, D2 is 16, S is 14. In August 24, D1 returned 3 days early from a holiday with me/siblings to collect her A level results. Dad collected her from train station and took her to his house (former marital home), where his new GF was waiting. There was no prior notice/discussion with D1 about GF being there. D1 had met GF twice before, briefly for a meal/drink out. GF stayed there for 2.5 days, working from ‘home’, with all her belongings in the bathroom, bedroom and kitchen. It looked like she’d moved in. Daughter felt uncomfortable and wanted to chat with dad about it. This caused a row, GF left in tears, taking her belongings, saying she knew the kids wouldn’t like her. Dad didn’t speak to D1 for a few days, saying she had ruined their relationship and GF had left him. Since then GF and kids have clashed at every meeting. There were chats between kids/dad in October and November 2024, with kids asking Dad to have his relationship outside the home until they all knew GF better. This resulted in GF telling the children that they were just kids, and the adults call the shots, so she could do as she liked. Dad did try to honour the kids request to keep GF away, but soon caved to GF’s demands for more attention. In December 2024, D1 got a text message from dad/GF, after she’d had another argument with GF, telling her that if she couldn’t get on with GF she would have to leave the family home. Dad said it was his house and he would do whatever he wanted in it, with whoever he wanted. I offered for D1 to be with me 100%, but she wanted to continue 50:50 with dad. She is now at uni, but comes home w/e’s, so has limited time with dad now anyway. She still goes to dads but comes to me whenever GF shows up. At Christmas, dad cancelled xmas day, boxing day and NYE plans with kids to be with GF. Kids were devastated. There have been rows and upsets virtually every time GF is at the house. The situation with GF and dad also seems volatile, with at least 4 splits and reconciliations since August 24, with kids being blamed for ruining their relationship on each occasion. D1 and D2 have now said they want nothing more to do with GF. In response Dad has said GF is going to be coming over more and staying overnight more. I have minimal contact with dad, we only text about child care issues, but I have messaged him to ask if we can discuss the situation, as I can see how upset the children all are. D1 suffering hair loss due to stress, D2 has become sullen and angry, son has become very quiet. Dad, as I expected tbh, hasn’t replied to my text. I am supporting the children as best as I can from my end. We discuss the rows and how they feel and what they want going forward. They still want to have 50:50 time with dad. I have bought them a book on blending families to read. I have researched online how to handle these kind of issues from the perspective of relationship professionals/counsellors. I would also like to get some ‘real life’ suggestions from parents in similar situations on what else I can do to help the children to cope. One friend suggested a family counselling session with self, kids, dad and GF. Is this a good or bad idea?