I have been exactly in your situation.
At that point I did not have anybody to look forward too for an advice;and ended in 11 years of misery(lies,marraige,separation,almost divorce,eparation long one,false reconciiation and then now finally divorce);

Both Leed and Rose,have asked you to do the best;
But this what I want to add 'Why do you thnik so less of your self;do you think you are so bad that somebody is justified enough to cheat on you;it doesnot matter whetehr you were married or not,dating and marraige are both commitments;and someone who can cheat you then and put it so lightly 'yes i was attracted...bla..bla...and then using you as a puppet or their ego-booster to wait for her till ,she,like a queen,decide what needs to be done next";

gain your confidence,come out of this mess now(to save you a life time of misery,tell her amicably in person or through other means that you have decided to move on and lead a healthy life ahead ;
Do not encourage her begging,if she does that wanting to come back;give her an insight that life is not a fiction or a game of attraction for some one to lose or win;we need to love,care and respect each other mutually;and that is what was missing currently with you too;

this is not justified,love is not supposed to bring any sort of drama or pain;this is in no way love for you;let her earn you,and you do not become a doormat please;

Also all the insecurites that you have been thru,i do not think it is worth all this;life is meant to be healthy and happy;there would be plenty of good honest women who would respect you and love you for what you are and not go about cheating on you;
Next time please do not jump into a relation or blindly trust;take your time and brfriend the person,know what nature she has got and see if she really is trustworthy enough of your love;
Please do not settle for dirt;you are uncomfortable now with her;and a relationship whose foundation is not based on trust wont last;it is msery,i know this for sure.