dude trust me..you do NOT want to know about the act itself...you may think you do...but you dont. trust me on this
Ive given a lot of girls a lot of 2nd chances. Guess what, WITHOUT exception they cheat again.
and whats the confession going to do?
you have to ask yourself what it is you are fighting for? you want to see her squirm and feel terrible and guilty confessing what she did to you? come on man
right now it comes down to how you want her to remember you as. A Stand up Man who could just walk away proudly with his head held high? Or as the guy who pushed her to break down in front of him so he could get irate and yell at her and make her feel terrible for some kind of ghostly "revenge" satisfaction?
I think in your heart you know the right thing to do.
besides we will all be here if you get bored without her around..lol