I'll admit, I got all oneitis for this one girl, and I realize that part of that is because I didn't follow one of the main pillars of inner game: having your own boundaries. Let me explain:

You are a High Value Man, And You Have Boundaries

Some people in general will try to take advantage of you, and this happens all the time in dating. This is not always intentional, but many guys will put up with a girl's undesirable behaviors simply because she's hot or have a built up idea of what she is and ignore her negative traits. Remember what you're boundaries are, and stick with it.

My Personal Experience

The girl I have oneitis for, I put up with a LOT of shit I would never usually take. We'd go out, she'd flirt with other people, get other guy's numbers behind my back (she'd be really sneaky about it), and in one case came back home with me... was too tired to hook up, and I found out later was actually texting other guys FROM MY BED how cute they were.

In a nutshell, this girl was a complete validation case, and just seeked validation all the time. If I were to text her, she'd respond but rarely be able to go out... then if I decide I wasn't going to contact her, she'd suddenly text me, and on occasion want to hang out.

I'd escalate, go for a kiss, and then get cheeked EVERY TIME (in the beginning we started out stronger, some makeouts... but that died out after distance became an issue.) Sure, I messed up a bunch with her, but in the long run, it seemed like she keeps me around for validation and as a plan B.

Crossing Your Boundaries

I don't find it very attractive to have a girl have no idea what she wants, flirting with other men while out with me, and texting other guys super flirtatious things from MY BED behind my back (I go to take a piss... come back and she's "sleeping". I found out through another guy who showed me the texts he received from her and the date/time she sent them). That crosses my boundaries.

Cutting Them Out

This is the tough part: walking away and letting go of a girl who crosses your boundaries. No matter how pissed you may be... there is often a small sliver of hope that this isn't how they actually are, and that they will change and things will work themselves out. I struggle with this myself and try really hard to cut out the negative influences (suggestions are welcome...) but that small sliver of hope keeps me from doing so. However when I logically think about it, life is too short to deal with someone's bullshit (something I'm not so clear on is do you call them out on it or just cut them out of your life?)

TL;DR: Know what you will and will not put up with. Don't let people step all over you and stick to your boundaries. It's tough, and something I struggle with from time to time (especially if I've put a girl up on a pedestal already), but you are high value who knows what he wants.