Should I be mad about my boyfriend's "girl" friend on myspace?

[calichick]

Today I went into my boyfriends myspace to see if a message I had sent went through and I happen to see some messages he was exchanging with some girl he used to go to high school with. I'm 19, hes 21, been together 5 years by the way. I'm not gonna lie, I took a look because I was curious. Basically, he messaged her first saying he found her on another friend's myspace, then they got to talking about school and how she saw him at the mall one time and he was with me and she was with her bf so they didnt say hi, then his last message to her says that she should say hi no matter who he is with next time and gave her his phone number if she wants to call him or whatever. Man, I got sooo pissed after reading this and it made it seem like I didn't matter and he's just freely giving his damn number out to people. So I dont know if I should make a big deal out of this and if I do bring it up, how do i handle the situation? It's like he talked without mentioning me...help!