does she like him?

Okay. So I'm 16 and so is my boyfriend. I lost my virginity at 15 and so did he (one month after we started dating). We have being together ever since. Today is our 10 month anniversary together and yesterday he went to a concert. I couldn't go my parents wouldn't let me. So he asked a friend of both ours who is a girl. I was a little upset that I couldn't go but I really didn't have a problem with it. But she seems like she likes him more than just friends she doesn't act like she does around him. I told him about and he said that he doesn't see it and he said that he was sorry for going with her and that he was a bad boyfriend for even going with her.