Make it about unity.
Fights, by their very nature, are divisive. They pit people against each other and, when they happen in a relationship, they can leave the couple feeling miles apart. Sex usually creates the opposite feeling. "It [makes us feel] less like we're two separately people and more one unit," says McGrath. After a fight, people often think more negatively about their relationship than is warranted; sex can be a good way to get back to a more appropriate emotional state.