You love your daughter a lot. I respect that.

He's hurting your daughter.

He already hurt you, now he's going to hurt your daughter.

Don't sit back and do nothing. Do what's best for HER.
What would benefit her?
If it is keeping her, despise the consequences, do it.
She clearly isn't happy at your ex's house, and she isn't safe.

Protect her. Everything you got.

You have my blessing. Good luck.