How to support DD through her dad blending families with his partner?

[eractually]

Co-parenting with my ex, 50/50 shared care of DD9, divorced 5 years. Her Dad will soon move in with his partner of a couple of years, and her kids. DD seems fairly chilled about it so am trying to take her lead and not make it a thing. However, it’s likely to be a fairly big change of lifestyle moving from a household of 2 to 5. She likes his partner and is fairly neutral towards her kids.

Her dad doesn’t communicate easily with me about this stuff, so most of what I’ve picked up about plans come from DD. Not sure what I can do to ease the transition for her, other than keep doing what I’m doing and maintain a happy and consistent home with me. Any similar experiences out there?

I don’t have the experience as a parent, but do as a child. I think the mos useful thing would have been to feel comfortable talking about the changes with a neutral party. My parents relationship was acrimonious, and so taking about the steps brought our a lot of negativity from my mom and a lot of denial from my dad.

It is an inevitably difficult transition, but ultimately it can be really positive or really negative depending on the circumstances. From my mom, I would have wanted to know she was ok with me having a relationship with step mom and children. I also would have valued a place to vent without judgement or follow through. And I probably could have used some coaching on resolving issues with my dad.