girls only need two things from a guy: emotional support and security.
if it's like what you said, she can't leave her boyfriend for some reason. and she has no one to cry her heart out to. hence she lacks emotional support. [i don't know whether her bf provides a sense of security.]
and then you came along and showered her with your care and concern. you provided her the emotional support that she needs. she realises that she can get her emotional support from you, hence she looks for you whenever she's troubled.
when she's gotten enough of the emotional support, she disappears without a word and you can't seem to contact her. she only appears again when she's low on emotional support.
in short, you're like an emotional tampon: used when needed, discarded when not.
bro, get this straight: you cannot change her because:
1) your position in her heart is not great enough to affect her thinking.
2) it is near impossible to make a person have a 180 degrees change in personality.
like what the other guys said, both of you belong to two worlds. just be glad that she crossed your path, because you wouldn't have learnt so much without her.
