That's victim talk. Having an affair is a choice. You didn't do anything to deserve to be cheated on, just as your husband didn't do anything to deserve you cheating on him.
There is no tit-for-tat; he doesn't get a free pass on an A just because you had one.
The thing to remember is that you made mistakes, and he made mistakes; but you have come to understand what you really want in a relationship, and you are willing to commit to working things out. If he is not, then he's free to go.
Me: 44, Wife: 39 M: 17 years T: 20 years Bomb on 08/25/09 1/13/10: MC started 1/28/10, 2/8/10: More bombs 8/28/10: Wife moved out No talk of D, no movement