Jealousy is a sign of "insecurity" over something that is already "yours".
Envy is wishing something that belongs to another was yours.
If the person you are dating/married to is a very attractive person then you can't expect other people not to notice she/he is attractive also.
It's like getting a job at a great company and learning afterwards other people are still emailing and faxing their resumes. Are you going to get upset with the company? Neither you nor your mate has any control over other people. The attention is unsolicited/uninvited. A polite rejection usually works.
Therefore it really makes no sense to be jealous of something that is "yours". It's irrational! Lets face it if you have anything that's "worthwhile" other people are going to want it too! In order to keep "your job" you have to continue to do your best work. A jealous person is looking for a lazy way out. They want to "relax" or feel secure in the knowledge they don't have to continue to give their best and their mate will not wander. However if you are not performing well at your job you are likely to be fired. The same holds true in your relationship. You provide your own "job security" by always doing your best.
What makes people angry is they want their mate to be rude to everyone but them. In some instances they may want them to only dress nice when they are around, find ways to avoid attention, or turn down their inner light/personality. Everyone is looking for someone who will love and accept them for who they are.
If a person has to "change" in order for their mate to be "happy" then they are wrong for each other.
However if you or your mate are flirting, using sexual innuendo with (other people), or making less time to be with each other then it's not a "jealousy issue" but a "betrayal issue". If someone is not "acting like they love and appreciate us" we should assume that they don't and move on. Actions speak louder than words!