A major component of jealousy, for many people, is the suspicion or resentment of the rival. In Kerista, on the other hand, the relationship that every man had with the other men and that every woman had with the other women elicited what they called "compersion" rather than jealousy. "Compersion is the positive warm feeling you experience when you see two of your partners having fun with each other. It's the antonym of jealousy."
Source: wiktionary