Re: quite a quagmire, need some help
I have to agree that a relationship is a bad course of action at this time. First off...I don't trust women who cheat. I know I never act like most dudes that they cheat on, but I never think that they couldn't do that to me if they felt justified.
She is going to have a bunch of mixed feelings if they do breakup. A breakup is a process and she will not magically move on from him. You're kidding yourself if you think she will walk away clean from him and go to you. She may not even want a relationship anyways.
It's best to just keep things casual right now even after the breakup. Give her time to re-cooperate if they do breakup before approaching her with a relationship. Trust me you'll be sparing yourself a lot of stress and heartache.
"All things are subject to interpretation. Whichever interpretation prevails at a given time is a function of power and not truth."