Interesting post on DivineCaroline.com. The author believes that jealousy can often lead to hostility and resentment in many different kinds of relationships. Often it comes from feeling insecure or threatened. You can fight jealousy by making agreements you and the other person are comfortable with. Open, honest communication can help resolve jealousy. Be patient and and work together with the other person to find a solution to jealousy.
Some good points on how to handle jealousy:
Handling the Green-Eyed Monster