When a couple gets to the last stage, one or both partners may have an affair. But an affair is usually a symptom of a dying marriage, not the cause. The end of that marriage could have been predicted long before either spouse strayed.
John M. GottmanI liken an affair to the shattering of a Waterford crystal vase. You can glue it back together, but it will never be the same again.
John M. GottmanI believe we're going to find that respect and affection are essential to all relationships working and contempt destroys them.
John M. Gottman