Hi Mia, my daughter is now almost 12, and I left my NXH when she was 3. He still has visitation. It is still a struggle. I have a very communicative relationship with my daughter. He did everything he could to turn her against me but has not succeeded. Everything is a popularity contest to him. I soo related to him wanting her to say she likes him best. My daughter has not seen a therapist and is truly thriving. What she has seen is my constant willingness to stand ground for her with him. She has found this comforting.
Occasionally I have asked him to see a therapist with me to work on agreements. I forced his agreement to go by saying I had some issues and I'd discuss them with either DSS or a private counselor at his expense. These sessions are very fustrating but ultimately I've gotten enough compliance on his part that I feel my daughter is reasonably safe with him.
He's always tried to put her in the middle- break one of our agreements and ask her not to tell me. My daughter won't do it, but she can say, "talk to mom about it".
My personal opinion is that, while therapy can be useful, what your kids ultimately need is YOU to protect and hear them. You could make a list of why your daughter doesn't want to visit and see if you can pressure, cajole or blackmail him into compliance.
Standing up to my NXH has made me stronger, more confident, and I see these traits in my child. She is an honor student, soccer star, and a lovely person.
Ns are bullies but they don't always win; they are their own worst enemy a LOT. Do what you can to block his emotional abuse of your kids. Don't just passively rely on a therapist to help them talk through the hurt- some of the hurt can be avoided, or at least I found this to be true.
Good luck, my prayers are with you,
Delphine