Should people forgive themselves for cheating?
No matter how consumed with guilt or shame they may be, it's not so much about forgiving themselves, but getting back up and making amends for what they did.
For starters, they must acknowledge that what they did was wrong -- no excuses are fair game!
Then, the cheater should own up to what he or she did and apologize without expecting their partner to accept the apology, let alone take them back. If the person finds it in their heart to forgive, then more power to them. But that decision is theirs and theirs alone to make, and the cheater should not bombard the partner they wronged if the latter opts never to speak to him or her again.
In life, for better or worse, we must deal with the consequences of our actions. Cheating is one of those areas where an "undo" button may not be available to us.
Most important, the cheater must learn from this experience and vow never to betray a partner's trust ever again. They must examine the factors that drew them to cheat in the first place and commit to ending any future relationship once the thought of being unfaithful crosses their mind. They need to understand that carrying on with an affair is not only incredibly selfish, but grossly inconsiderate of their partner's feelings.
What good is forgiving yourself for cheating if you end up doing it again?
Once your partner is unable to trust you, the relationship is flat-out doomed.