I must say if you cant' forget her and move on as Victor states so well "will give you an ulcer" and no girl is worth that except for Me!!! lol (trying to be funny in light of the heavy topic).

I am getting confused by all the vacillating really . I am a 30 cough something single gal so this is what I think if it helps. (Disclaimer: but this is not how we all think)) All i got is my own opinion.

I can tell you if I have a b/f , or am just dating someone or single, it doesn't matter who is "pining" if I don't know.

If I have a serious b/f , regardless of being told by "the piner" his feelings no matter how flattered, I would have to let them know there is no chance since i am seriously involved.

If i was casually dating someone (new perhaps) and the "piner" told me, i could have some choices to make.
First does the "piner" interest me?
If not again like above tell them the truth.

Secondly if i was interested , I could:
1. State I am dating someone new but we could also go out casually or
2. Decide I am more interested in the "piner" than the current casual date, and make that known.

So I don't think it matters who or where she is at she isn't married if you really still want to , need to tell her. Do it. Anyone else in the picture isn't really your concern you are just being honest and the ball is in her court at that point.

You kinda have to drop the whole thing and forget it or toss the ball out into the court, or get an ulcer.