Unfortunately, I think you're headed toward heartbreak on this one. ..
..
Nobody who's truly happy in a relationship is so eager to "shop around." Almost by definition, being happy means you're not shopping around. ..
..
So I think you should let her go -- break up with her. Tell her that you don't feel comfortable being in a relationship with someone who's way less committed to it then you are. ..
..
If all goes well, she'll realize her mistake and come back to you. ..
..
But of course there's a good chance she won't. ..
..
I realize this advice might be easier to accept in principle than to practice. ..
..
But you sound like a good guy who will be able to find a relationship with someone who feels as strongly about you as you do about her...

She's flat out telling you that she DOESN'T want an exclusive relationship, if you do then you're with the wrong girl...
..
As hard and as painful as it'll be, you have to make a decision to either be good with that or move on, that's all you can do at this point...
..
Angie..
..
I'm the yin to Carlos' yang .....

Oh, so what you're saying is that she wants the best of both worlds? The comfort and security of a relationship, but also the freedom and flirtatious fun of being single? The big ol' plate of cake in front of her, yet also the taste of frosting in her mouth?..
..
Her carpe-diem attitude about the future means that she's setting up her own excuses, buying some insurance against the day she meets someone who excites her more, or the day she gets bored with you, or the day she feels like a change. When she says "You never know what's going to happen in the future" what she really means is "I know exactly what's going to happen in the future: I'm going to meet someone new, but while I'm waiting I guess you'll suffice." Tell her that opportunity's knocking now and that she gets her wish to be freewheeling and fancy-free -- early!..

Well it sounds like she's pretty young so I can understand that 'wanting to play the field' business but if you're not in that state of mind then unfortunately it doesn't look like this will work out...
..
I don't think there's any point in hoping for the best here...I would break up with the person and let them find their own way...Most likely she will come back to you anyway but I'd say she'd have done too much damage to you by then so you should cut your loses :(..

Yeah, I'm not so sure that she wants to stay with you. I might just go ahead and break up with her now. I think it's reasonable to not be in a committed relationship in college -- especially if she's been at an all-girls school, she's probably eager to go to school with boys and see who she meets. It seems like you and your girl both want different things. You want to be committed and exclusive, she doesn't. Can you deal with dating other people? If not, say goodbye. Because it doesn't sound like she is going to change her mind...