Here's how I would look at it- at best even if he agrees, it's pretty much going to be unenforceable, right?
Maybe there is a way that you can soften the language while stil making your point - like no overnights unless they have been in a relationship for X amount of time.
I know this one is tought to swallow and I have nightmares that this is what life will be like for my girls - but I don't thinkg there is any way to make this type of promis legally binding. I think the best you can do is plant the seed that reasonable people would consider this type of behavior inappropriate.
