Ha natural trait im afraid
Well i really think you need to asses where you want this friendship/relationship to go ..I would Not condone any form of cheating even a peck is a betrayal in eyes (thats just me im fiercely loyal (another downpoint to my personality)
My husband cheated on me 9 years ago have never forgotten it never will , i had however moved on from it until i was sat there with my husband and some of his friends 2 months ago until i realized that that one of the girls was her felt like i was back in that horrible place all over again ,i think thats where my doubt is creeping in again as i know they are friends on facebook too he just thinks because i forgave him its forgotten..
So please dont do anything hasty make sure your marriage is actually over and move on , but if you dont do it properly it could cause a world of hurt for your wife and daughter not that breaking up would be easy anyway but at least without the hatred ...
Hope some of this puts it into perspective :)