I think once your genuinely fall in love with someone a part of you will always love them.
I was with the same boy for all 4 years of high school and now I live across the country and I still feel love for him (or the idea of him) even after falling in love with my current boyfriend.
It can be scary but it is probably the most exciting emotional connection I've had in my life. As for how to fall out of love... I'm not so sure. My high school sweetheart stomped all over my heart and that didn't change anything. I think a complete cutoff of communication might help... or make it worse.

Time helps.
Just do what makes you happy.