unhealthy relationships

the girl at the job i recently left was/is just as much a part of the disaster that i left behind. i thought that maybe she had the patience of a saint, or was just forced to bide her time until a new opportunity was available, but i guess just like anybody else in an abusive relationship, she was doing her fair share of keeping it going, somehow. or maybe she's just so terrified of displeasing the woman that she will do ANYTHING she asks, including showing her the text messages that she and i exchanged privately.
i don't imagine the girl showed her the texts we exchanged that talked about her job interviews or the one in which she thanked me for defending her in my resignation email.
i sent her a text this morning that said "why did you show _____ my texts?" her response was "she asked."
i just have to let it all go. i left that place for one reason, but other reasons seem to be reinforcing the decision. i just can't understand why this girl would betray me like this. or maybe i can. maybe she's just too scared to say no, to adhere to the promise she made not to talk to her boss about this, to stand up for her and my rights to privacy. i could be vengeful and spill the beans about her looking for new work and her plans to quit cold turkey when she gets it. but maybe the poor girl isn't even really looking, and just needed someone to listen to her when she said she couldn't take being screamed at anymore.
i'm doing the best thing i can possibly do in this situation, which is to close all doors of communication and leave it all behind me. i was feeling a little confused as to how i felt about this whole situation, but i have finally figured it out.
i am offended.