I'm gonna send her this email:
"Our culture is so pervasively infused with this idea of love being a necessity in life that I will take it from any source that wants to give it to me. I'll do this even if I don't feel a mental connection with them just because I want that feeling of being totally accepted and wanted by someone. Is this appropriate, though? Should you really be giving people pieces of yourself like that when you're knowingly giving the other person pieces of your puzzle that do not fit in their puzzle? Is being in love simply having a beautiful person that has consistently great sex with you, is really sweet/supportive, stable, makes great food, makes you feel comfortable, and is pleasant to be around? That's certainly everything you need for a good lover. Is it what I want in a relationship? It's definitely a now required part of it. However, the most critical component for me here is friendship. How am I going to spend time with someone I can't talk about the aspects of life that I'm passionate about with? Can I grow as a person with this girl? The answer to both of these questions is that I can't with you.
Even for a couple months, I can't be selfish and tie down a person as wonderful (I mean this, you are a great girl) as you from meeting other people because you're in an exclusive relationship with me. Your twenties are meant to be enjoyed. We only have superficialities in common. Who knows, maybe you'll meet someone that is extroverted, muscular, happier, and likes to dance.
Sorry. Letting you go pains me quite a bit. If you want to talk to me about this immediately, do it through email. I am awful at articulating myself in person when the emotions are still this raw and I'm highly suggestible. If you still want to talk about this, call me in a couple weeks.
Best of luck,
blueline"