I maintain there is no fault or blame to assign. Affairs have to do with lack of attention to addressing past trauma, low self-esteem, and the basic selfishness all of us human beings allow ourselves to fall into at times. Affairs are a function of where we are on our path to self-awareness, self-actualization, and self-love. And some of us just aren't very far along on that path. Now the fact there is no blame to assign does not mean we are not accountable and it is prudent to attempt to make amends whenever possible, when it will not do more harm than good. AA Step 9 is a good model to follow: "Made direct amends to such people wherever possible, except when to do so would injure them or others." In other words, don't out your lover. It's on HIM to confess if he so chooses.