How to Approach "The Talk"

[Saga]

Hello,

I've been dating my boyfriend for 8 months. When we're together, we get along great. But I don't feel like I'm a priority in his life. It seems as though we just hang out when it's convenient for him. And whenever we do hang out, I usually have to initiate and/or wait around for his response. Case in point- I told him I have a busy weekend ahead with work and rehearsal and that tomorrow (Thursday) is probably the only day I'll be available to hang out until next week. I still haven't heard anything from him about plans for, well, today now. On a side note, his cell has been off for the past month and will be the next month so since he very rarely calls me (even though I've told him more than once that I really appreciate when he calls- I thought that was a hint) I usually have to wait until he's on facebook to talk to him, or call his mother's house.

Anyway, I feel like I need to have a talk with him because while sometimes he makes me feel special, I'm not sure what his intentions are, and I just get frustrated that I seem so low on the list. He'll call me beautiful and sexy, so I assume he's still attracted to me, and I don't have reason to believe he's cheating, though he does have a lot of female friends. I've asked what a relationship means to him and he said "having someone to hang out with who means more to me than a friend." OK...I suppose that answer is acceptable, but anyway, how would you suggest approaching this talk without seeming too attacking? What is the best way your girlfriends/wives initiate talks with you when they're not pleased with something?

Additional info: we are both adults (25 and 22) but we both live at home. I'm older and I've been on my own for 7 years in the past, but he has never been away from home. He's also a mama's boy, but his (single) mother is disabled and is VERY dependent on him to drive her everywhere, etc. That kind of plays a part in everything because our relationship is based around his family.