What do I do if my soon to be ex repeatedly has people watch our 1 year old for hours and refuses acknowledge it?

Divorce is not final and there is no judgement yet. On multiple occasions, my soon to be ex-husband has people I don't know or women he hooked up with in the past watch our 1 year old. The worst part being, he pretends he didn't have a sitter, never acknowledges it when I ask, and purposely lies. So I don't even know if she spent the night with complete strangers while he was out or if our daughter stayed with a family member. When I ask (if I can even piece together that it happened) he refuses to admit he even had a sitter, let alone attended an even as innocent as a wedding. His most recent answer was "I can't remember if I went to that wedding or if I had a babysitter". I go out of my way to make sure only people he knows watch our child and that he has an opportunity to see their home if she goes there. And that he is well aware ahead of time. Especially if it's a full evening event. However it's very rare for me to have a sitter for much more than an occasional doctor’s appointment or grocery store run.