My 13 year old son has been friends with a girl for a couple of years now. She's a lovely girl and they both get on really well. She's recently had a falling out with her mum. They've grown a bit closer the last couple of months and the other day my son asked if she could come over. I agreed and then today they went out for the day and had a great time by the sounds. It seems they're now girlfriend/boyfriend as I saw them kissing as she left our house. I talked to him afterwards and laid down some ground rules and spoke about sex. He's a good lad and definitely didn't like the sex talk. Is there anything else I should do?