Changing Custody from Joint to Sole

I currently have joint custody with my husband(we are still technically married). However, I feel like he is exposing my daughter to unhealthy situations. One of which, he met a woman online who lives in VA, I found out that he has taken my daughter to Virginia yesterday and they are all sleeping in the same hotel room together. My daughter has never met this woman and I feel like this is not healthy for her, not to mention he and I are still not divorced yet.
How hard would this be to change and what steps would I need to take to change it? He makes so much more money than me and I just feel like it may be a lost caused but my daughter just has enough to deal with besides him taking her up there so he can do what he wants with this new woman.

Thank you

If there is a custody order in place you will have to demonstrate the occurrence of a substantial change in circumstances which affects the child’s best interests. Unless this woman is somehow dangerous my opinion is that the court would find that this particular situation does not warrant a change in custody.