To boyfriend or not to boyfriend? That is the question.

How do you break up with a boy and still remain his friend? I mean, in my book, you can't just say "Gee, Charles. It was average while it lasted but eventually your putrid breath and lack of personality just got to me. In fact, if we keep dating, I may have to flee the country just to get away from you. But I would really like us to remain friends." Charles would be one sad man to stay friends with someone who broke up with him like that.

But that's kind of the predicament I find myself in now. Although he is sweet and funny, I just don't think we make the best kind of couple. Someone can be a good boyfriend and someone can be a good girlfriend but that doesn't mean that they are good for each other. I just find myself in between a rock and a hard place (so that be two hard places) because:
a) He cares about me much more than I care about him (I mean, he's talking love and wedding vows). I feel like I'm such a heartless girl because I don't return those feelings at all.
b) His best friend (my neighbor from last year) is one of my really good friends. She explicitly told me (in a joking way) not to break his heart. And I feel like I'm going to do just that.
c) I don't know how to do it because we live about an hour away from each other. I don't want him to drive here and have me break up with him but I also don't want to drive there and be in an awkward situation. But I think over the phone might be a little tacky... However, via text is the best route in this situation I'm thinking. Clean, simple and if he tries to make it difficult, I just don't respond, right? Yeah, okay, no texting.

Also, he has a trait that I don't really care for. His high level of interest in marijuana and alcohol is one thing that I really don't like. It wasn't until after we started dating that I realized he liked to smoke. He claimed that it was a habit he was breaking and something he did more out of peer pressure than personal gain. But to this day, the habit has still not been kicked. Oh, and did I mention that his best friend is a drug dealer? He has admitted that smoking pot has impaired his memory and made him less motivated -- yet he can't seem to stop. It just really frustrates me to see him so consumed by it. And it doesn't make me feel better that he blames it on his pot-head friends. Doesn't that just mean that he isn't strong enough to hold his own and tell them no? Since I don't drink or do drugs, I don't see the point in it. I feel completely competent without the aid of those things. I still manage to have a good time without them. I just feel like if we keep dating, he would try and pressure me into doing stuff that I really don't want to.

I just feel suffocated in this relationship right now. Especially after going to China I feel like there is so much that I want to do with my life and I just feel so tied down by being in a relationship. I feel like I always find a boy, get attached and then realize that it isn't going to work out when it's too late. Becoming a nun has never sounded so good.