How to Eliminate ONE-ITIS

Q- So if I forget about her and move on, then I'll get her?
A- Get that out of your mind. Time and time again, I've seen buddies who only go after girls in hopes that the girl he's "forgotten" about will get jealous and chase him. Not gonna happen.

...and if it does happen, once you come around, she'll drop you again in seconds. Accept the inevitability that she has to be tossed aside.