Often, as mental health professionals, we focus a great deal on the individual who was cheated on, versus the person who did the cheating. The general belief (and myth) is that the person who was unfaithful is 100% to blame for the dysfunction in the relationship. People usually see the cheating itself, which is actually one of the by-products of long-term, ongoing relationship dysfunction. As a mental health professional who works primarily with couples, it is important to have each party be accountable for his/her negative behaviors in the relationship, and decide what he/she is willing to do in order to sustain the relationship. Both parties must have very clear expectations moving forward. Yes, the unfaithful person must admit to wrong-doing and admit to causing emotional pain to the partner. The other person in turn must be willing to forgive and move past the transgression. There cannot be continued bringing up the past, or else there is no way to heal.