She made her stye, let her lie in it. Seriously. I know it's easier said than done, but the lingering guilt you have will dissipate with time. You didn't cheat (even if you did, who could blame you?) and she made it a thousand times easier for you to bow out gracefully. Consider it a blessing in disguise, my escape wasn't so easy. I was 19 at the time (28 now) and he made my life hell and stalked me for over a year. Some pretty fucked up shit went on and it still took forever because NY didn't have stalking laws at the time. Nobody should have to deal with what I had to.