Im so upset 😭😭😭

The father of my children got with one of our friends and she has 3 kids also.... all girls. I dont mind that he is with her, not at all. Its been 5 years and iv more than moved on... however my kids spend weekends with their dad and his girlfriends little girls ALWAYS have head lice. This is becoming a huge issue. They swear its taken care of and then my kids come home and its a repeat of the strip beds treat hair wash everything routine thats been going on for weeks now. I have 4 kids and one on the way, 3 by my ex and this is getting to be an expensive time consuming process.

I dont want to keep the kids from their father but its looking like at this point i have no other choice.

I cant keep battling this with a 6 person household.

How would you ladies nicely handle this as i dont want to damage our co-parenting relationship which is already fragile to begin with.

I just need some advice. Thank you ladies!