I'm at war with myself over a friend, help?

My friend, I have heard this story so many times, and it always makes me sad because there really is no easy way out. First let me say that unless you are gay, it is virtually impossible to start out as friends and not ending up falling in love. People think "sex" equals love, but NO. Once the sex thing wears off, what you want is someone you truly LIKE (i.e. friend) for the rest of your life. (been there-done that). I always say "the truth will set you free", so there it is. You have to tell her the truth: that you have fallen in love with her; that she obviously has chosen someone else; she MUST let you go if she has any feelings at all for you. If she cannot do this, you will have to because NO TRUE FRIEND WOULD KNOWINGLY CAUSE HARM OR PAIN TO SOMEONE YOU LOVE (OR LIKE). Eventually, you will learn from this experience and put it behind you while at the same time knowing what it is you seek in a love partner. Best of luck!