Hi D.
Another D. here too, also a stepmom with custody (well hubby has it), what a coincidence huh? I dont believe you have any legal recourse, unless there is something in the original court order regarding overnights with not married people (however it is worded).
I understand your worry and concern, I just havent seen anything that makes me believe you have legal recourse. As sd ages she will decide on her own which relationships were healthy that she watched, hopefully you and your husband can impress upon her more, and can instill the morals you would hope to into sd.
I could be wrong though. I dont know how friendly, or communicative the relationship is between mom and dad. Does she inform your dh of person's name? Can you search court records, maybe even sexual offenders databases etc?
I wish her mom would understand that this isnt healthy for a child. One of the things that I had to learn, is I can not change other people. I dont mean to sound all gloomy, hopefully another person will have experience to help you. We just watched it happen for years, had to trust mom, that was a huge reach for us. Things have settled down some, she is on marriage number 4 though, a little improvement as in they arent boyfriends for long. LOL
Chris M- Since I cant figure out how to reply again I had to edit my advice. I wanted to be sure that you saw they already have custody of the child? The mom is not the custodial parent, and I dont know if your advice would be the same.
D. W- DO document everything you can, journals, any proof you get via other means etc. If nothing else you can proove she is unstable should she attempt to get custody.