Does your dd know the gf? If they are friends, I'd probably have them share. Otherwise, I think you have to ask both parents. If one says no and won't budge, you could always put the gf in with your dd and turn a blind eye if the gf moves to your ds's room.
18 year old DS is going out with 16 yr old girl, and has been for 3 months. Both have slept over at each other's houses, but each 'guest' has been given their own room.
We are aware that the they've gone 'all the way' , but we don't know if her parents are aware.
So we are going to a family New Year party in another part of the country and DS has asked if girlfriend can come along. All fine with us. But we stay in a local hotel and need to accommodate us, DD (15), DS and girlfriend.
So, do we let them have their own room without discussion? With discussion and the ok from her parents (who are divorced, so may not give the same opinion)? Do we have the girls share a room?