Jealousy in a dream commonly reflects comparison -- a sense that someone else has secured something you want and don't yet have, whether that's attention, success, or security. The feeling usually says more about a perceived lack in your own life than about the other person, and is worth examining from that angle first.
'Tis ill to begin any lawsuits or other controversies when the Moon is ill dignified: the plaintiff without doubt will be overcome. - William Lilly (1602.-1681.)