Teenage son wants to have sex with his girlfriend. A little unsure of how to approach this.

My middle son is 16 years old and has been with his girlfriend for about 7 months or so. She's a really great girl and has been over our house a lot. They have known each other since childhood. They played on a youth basketball team together and have been friends ever since. Both kids still play and she comes over to practice often since we have a decent half court. She has also made my son into a better student.I say all that to say we really like this girl and the relationship has been beneficial. I just wanted to point that out before people start telling me that he is too young to date.Anyway, he came to speak to my husband and I in our room last night to ask if he and his girlfriend could have sex in the house. He already has condoms. We talked about how to use them correctly back when we had one of our sex ed talks and he said that he knows how to use it properly. He said that they aren't allowed to have sex at the girls house because her parents won't allow it.I want to make sure they have a safe place to do the deed, but I don't want to go behind the backs of his girlfriend's parents. They obviously don't want their daughter to have sex and I want to respect that. I don't want my son having sex either but I understand that he is at the age where this isn't completely unexpected.Question 1: What do I do?Question 2: If you didn't want your daughter having sex, how upset would you be if you found out her boyfriend's parents allowed it in their house?This is my first time experiencing something like this. I waited until after I finished high school to have sex and my older son didn't date throughout high school, so this is a whole new world for me. I appreciate any help. via /r/Parenting http://ift.tt/2lJkbBU