Girlfriend causing problems around my child

I am at a quandry as to what to do. My ex and I are supposed to be trying to work on a custody mediation between us without going to court. At first I thought it would be fair to have joint (equal time) custody - alternating week to week. Now I’ve learned that he has brought a new girlfriend into the picture (during the weeks he has our daughter), and she cusses like a sailor around her - and he does nothing about it. She is only 7 yrs old. She also has been trying to turn her against me. I know I’m not supposed to let grudges or anger (towards my spouse) be used in determining what’s best for my child. But from what I know, he is head over heals with this woman (who is my niece, by the way) who parties a LOT…and he has let his morals go out the window. He also is letting his 16 yr old daughter (from another relationship) babysit our child while he goes off on these rendezvous for many hours at a time.

Do I file for primary custody to try to keep her in a safe, stable environment? If I do, he’s still going to get her every other weekend (at the least), and I will still have no control as to what he does or who he has around her…but at least it would be on a more “limited” basis. And should I get awarded temporary custody (until we go to court – as I’m sure he will never agree for me to have primary custody)…then can I also ask for temporary child support? He claims he’s not working and has no money to help pay for our daughter’s clothes, school supplies, etc; but he has money to take his g’friend out on dates. If he’d stop long enough to WORK, then he could make some money. That is not my fault. And they go by his “potential” to work rather his “want” to work, correct? (He is self-employed).

Very, very conflicted as to what to do in my situation. I’ve never wanted to take my daughter away from her daddy (normally - he is a good father), but I also need to ensure she is safe and has a stable environment.