Hello Debra

I have a 16 year daughter and we certainly would not let her stay at a boyfriends house, she has had a few boyfriends but none that are 5 years older that her, and like you would feel very uncomfortable about the relationship. It sounds as though she is trying to grow up too quickly which is exactly like my daughter. I think at 16 they are so vunerable, at 21 her boyfriend, I guess will have had some sexual experiences with girls (especially as your older daughter thinks he is a player) and she may feel pressurised into having sex with him.

I echo what all the other ladies have said re getting to know he better, maybe let him stay overnight in your house (in separate rooms) until you get more comfortable with the situation.

Not easy, good luck