I just mentioned this in the Avatar thread...
I had a pretty similar situation to this movie. I met her through work, and she immediately took over my thoughts. We liked the same stuff, but she was a tad quirkier in her interests (she was actually a fan of The Smiths). We started dating (she did say she didnt want anything serious), spent all of our time together, we grew ridiculously close...like...stupid close. We shared everything and spent every moment together and things got a lot deeper than either of us thought they would. And then one day she basically said "I'm done with you...hey...I always said I didn't want to be serious" and for no reason she stopped speaking to me. She met another guy not long after and they got married after a very brief dating period. It was weird, and I don't think I'll ever get closure to that.
So, this movie destroyed my emotional state. It was an absolutely amazing film though...loved it!