Good People have integrity. They don't risk their relationship for a fling with someone, or because they're craving validation thru seduction and sex.
Good People weigh the probable consequences of acting on their impulses, and make decisions which reflect their level of personal responsibility and character, because it's at the baseline of their sense of morality.
Those who act without morality are lacking in character. If you cannot keep a commitment you make to someone and consider how your actions will harm them, you have no business being in a committed relationship, because you lack empathy.
When you lack empathy, you have no internal governor that helps you determine right from wrong, and you do not experience feelings of remorse.
Sociopaths have no empathy or feelings of remorse. Remorse helps us learn what NOT to do again, because guilt feels shameful within one's core. Without access to feelings of guilt and shame, unconscionable behaviors continue to denigrate one's own soul.
If your soul is in disrepair, living life as a moral and integrous person who has character and empathy for others, is quite impossible. Thus, harmful compulsions remain alive, continue to be acted-out, and no redemption is possible.