[J_is_my_initial]

My dd was 18 when she decided she wanted to live with a guy. It was either try and help them out by letting them live with us or having her go live with his family and not being as close by. She is our only child. They were planning to get married even though they were young. They had run of the mobile home, but had their own room of course. They knew from the start, it was to help them out, but we had rules. They did get married and finally we bought a new double wide mobile home and left our single wide to them which they were making payments on.
I say if he can not abide by your rules, or even if it is a case of you have had enough, evict him. But be prepared for your dd to probly leave too.

As for them staying together forever at their age, it may not have been that way for our dd, but dh and i married at 18 and this dec will be 30 years. so it can happen.