bf has new friends that I don't know about

[mezmerist]

I'm not sure if this is normal, so I'm hoping to get people opinions and maybe others that can relate. My boyfriend gets along with everyone, but only has a few close friends. I know his close friends. I don't know ANY of the people that he is acquaintances with, which is fine to a certain extent. However, my bf seems to continually make new "friends", esp when he travels with his best friend. His best friend seems to know girls from all over the country, and when they go travelling, it seems that my bf ends up befriending these people to a certain extent. Usually, they just exchange numbers for the evening and never use them again, but sometimes there'll be a little communication. There's one girl recently who he has not only exchanged numbers with, but email. And it seems that they may be emailing back and forth right now, but I'm not sure. Is this normal? My boyfriend does not tell me about ANY of these girls, because he says they are not important, and he cannot report to me every time he meets someone new. And that they are not important, and I already know the important people in his life. I cannot put myself in his shoes because I never make new friends like that, and I don't exchange info with just anyone. My bf is also a very private person, so it's not like he's open about the rest of his life and secretive about this. He just doesn't talk about a lot of things, so this is actually on par with his personality.