relationships can be hurtful, and I can understand where you're coming from. After all, I'm about as jaded towards girls as its possible to be. However, carrying around vengeful feelings towards her won't get you anywhere, and you would do well to work on just letting her go sans the anger.
Just out of curiosity, though, you say you "figure out what is going on", but you never explicitly say whether this is something she (or someone close to her) told you, or if this is something you figured out on your own. If you came to this conclusion on your own, you should be very careful about how attached to this idea you become, as it is more than likely a case of overanalyzing the situation. Overanalyzing things like this is an easy trap to fall into, and is almost always wrong.
If you got this information second hand, it may be a little better, but I suggest you consider the source, before you take it as fact. If she did, in fact, tell you this herself, then you're best off taking her word for it, and moving on. But, again, don't leave this thing harboring anger. It won't get you anywhere.
One other quick note (and I don't mean this in an offensive way, so I hope you can take it as its intended), but from reading your posts here (I realize that this is an extremely limited sampling of what you're all about, but its all I have to go by), you sound like you may be a bit on the clingy side. You may want to examine yourself, and see if this is the case. Most girls do not want a clingy guy. They need a guy who is there when they need him, but will give them space too. Again, look within yourself, and determine if this is the case. If it is, it would be to your benefit to make a point of improving this aspect of yourself.