Man that is LAME!!!!
:o
I have a friend who really loves his gf but he cheated on her and didni't feel the smallest bit of shame. He really loves his gf but realizes he's still young and wants to sow his wild oats. I don't think it's right what he did, but in some twisted way, he feels more drawn to his gf now than before because he realizes that she's the one he wants. I'm sure she'd flip out if she knew he did that but as a friend of his I'm obligated to keep my mouth shut.
I guess the consequences are all in the person who got cheated on. They can be angry and break up, or they can forgive, but maybe not forget. Just don't use this issue as a get out of jail free card to go and cheat on her now.
Plus, my opinion of the relationship changes once I know i can cheat and not get dumped, or know that I could just get away with it. My ex told me flat out she loves me so much that if I cheated on her she's stay with me because she didn't wanna lose me. I never would have cheated, but my perspective on the relationship changed.
Just don't let her think that because you forgive her this time she can get away with other stuff.