First, a side note: I was actually coming here to post about a struggle I'm having with one-itis, then I read your post and weirdly enough it's kinda helped me out.
Dude, your fucked.
This kind of game is REALLY hard to play. Remember that women are far better socially calibrated than we are, their brains actually have MORE receptors for social cues and body language than we have! Because of this, you will subtlely give yourself away. Period.
However, the best way to deal with it that I've found (aside from the best one which is to screw 10 other girls

) is to begin to push her out of your mind. Make yourself BE done with her. Once you've finally set your mind on the fact that it's kaput-ski, the emotional gears switch to getting over it, and then you might stand a chance, but then also...
you may no longer care to.
I'm dealing with it to bro. I met a chick (smart sexy and wealthy) who I slept with this weekend. She's the first girl of quality I've slept with in 11 years (I'm recently divorced, then started on the path to pua). However, I used to be a natural before I met my wife, and alot of those skills are slowly coming back to me along with all this wonderful new shit I'm learning since finding the community. Anyways, made the girl cum 5 times, I shoulda had this one in the bag, but then I can't stop thinking about her, and each time I do I get happier and happier, until finally, I'm "twitterpaited".
Already have started to fuck things up to the point where I think it's probably done (although maybe not, we'll see). So I'm "throwing her out of my head." Everytime I think of her I tell myself, "It's done." then I show myself why it is. I then start realizing that the girl I'm falling for isn't who the girl really is (is yours?), they never are.
Then she starts to become just another girl and you start to see your not fighting your emotions for her, but your just fighting your emotions. I hope this is making sense
So, keep telling yourself "it's over and done with." Follow the logic to it's conclusion (example: I'm not going to call her, it's done. Even if I do call her, I'm to weird right now to play good game. And if that happens she's gone. If I don't end up calling her, it's done. So either way it's done, although with me not calling her it'll be done without me having to suffer humilation as well. So I will not call. (emotionally start to try to move on)).
Also, it's baby steps with this process, the emotional turmoil receeds slowly. Really fucking slowly.
Remember, don't approach one-itis as if it's love, cuz it's not. One-itis is addiction, plain and simple. Just instead of it being crack, or heroine, or cigarettes, or alcohol, it's to the idealized memory of a person. Treat it like an addiction, kick the habit. Do it cold turky.
good luck bro,
Tempest