How do Amanda and Elyot's feelings differ on the abandonment of Sibyl and Victor?

The thought of Sibyl and her unhappiness makes Amanda grow solemn. She feels terribly guilty about enjoying her time with Elyot, all the while knowing that she took part in an act that hurt two people. However, Elyot believes that the break was for the best, because it would have been much crueler to stay with their spouses and knowing full well that they were not in love with them. In his eyes, hurting Victor and Sibyl now is the better alternative to hurting them later.