Is jealousy rational?

dawnd and akienm are holding a local workshop on jealousy issues, tonight, so I thought I'd toss out a few contemplations...

Jealousy, particularly in polyamorous settings and groups, seems to me to be an attribute that no one wants to admit... the closest thing to labelling a "bad" emotion. But it is commonplace, IMO... and possibly rational.

( a few notes on the topic... )