I know how you feel. last weekend my supposed RAH soon to be EX came to drop the girls off. I was anxious ALL.DAY. Just the mere thought of spending 120 seconds in his space just gave me such anxiety. So I know how you feel. Ugh when he pulled up -gross - and gathering them and walking in the house felt like slow motion. So it's not trivial, it's real and I certainly understand.
I have to agree, unless there is someone there that you trust that can keep an eye on her, I would say you have to go. Or go and get her after an hour or so before everyone is completely trashed.