i think well from what i know what could really be happening is that she can also be a big flirt and girls can forgive people its not like they will forgive you so you have to forgive them...i think you should try to work it out but try to talk to her and spend as much time with her as you can and see if she is cheating or not like if she never wants to hang out with you or doesnt really like talking to you then something is up but if you hang out with her more she will probabaly stop all that flirting she does with guys and just think about you the only guy she has to think of and nobody else but if she keeps doing the same thing then give up or let her go some times when a guy leaves it teaches the girl a lesson so then she can realize that she made a horrible mistake