My partner and I have been together for 2.5 years and recently decided to move in together and rent a house. We've been effectively living in each other's place 5-6 days a week for almost 2 years so we're confident the next step won't be a big shock.
I've got 4 daughters, eldest off to uni soon, a 16, 12 and 11 year old. My partner's got 2 daughters 11 and 8. Until we told them about the move we'd all got on fine. We've been really careful from the start about spending more time together, not staying over until 6+ months and then gradually more so the kids didn't feel a big change. My kids get on well with my other half and I get on well with her eldest. Her youngest is very much like her dad and has heard his hatred, lies and fury towards her mum for 3.5 years since she left him. She believes his lies about me and her mum and is fiercely loyal to him. I've never said a bad word about her dad, knowing that to do so would fuel her belief that I'm a bad person. I play football with her and make every effort to get on. We knew the ex would go mad when he found out about our move. He's abusive, borderline psychotic, consumed by hatred for my partner and has always ranted and raved to the children about how evil she is. I'm also a target for his lies and poison, never more so now he knows we're moving in together.
My partner and I talk to the kids about their fears for change, moving house and how it might be living together. Every time we do it's constructive and relaxed.
The ex has now told his kids not to speak to me and not to do anything we ask. The 11 year old isn't so influenced and doesn't believe her dad's lies, but the 8 year old now thinks she's the boss and can tell us what we can and can't do. She refuses to speak to me and turns her back on me when I speak to her. She asks her mum to ask me questions when we have a conversation and hides when speaking about me. She's clearly uncomfortable with her behaviour but is also stubborn enough to maintain it, especially when her dad reinforces it and rewards her bad behaviour. We've got a few weeks until the move to try and restore manners and harmony, so if anyone has experience of anything similar or suggestions we'd be very grateful to hear them.