Jealousy: Love's Destroyer

Jealousy has long been deemed the guardian of love. But more often it's love's downfall. We typically blame our partner for paying attention to another, but the real issue may be what jealousy teaches us about ourselves.
Jealousy is not envy, although the words are often used interchangeably. Jealousy arises when a relationship is infringed on by a rival who threatens to take away something that is in a sense rightfully yours. But to feel jealous you need not have any sense of what that third party is like. Envy, on the other hand, derives from the basic fact that so much of the spoils of life come from how we compare to others. It arises when another person possesses some trait or object that you want, and includes a mix of discontent, a sense of inferiority, and a frustration that may be tinged with resentment.
Here's the shocker: Jealousy may be losing its utility in contemporary life, more useful to our ancestors than to us, given our penchant for changing partners. As our high divorce rate attests, sometimes, we're just not all that interested in saving our closest relationships. It may also be that jealousy is on a shifting course in our emotional repertoire, moving from coercive social emotion, a socially sanctioned response to infidelity, to sign of personal pathology.
The formula for jealousy,is an insecure person times an insecure relationship.But it's insecure people who tend to destabilize relationships and make them insecure. And a person who is very insecure is not just sexually jealous but jealous of any kind of friendship or even of a child - anything that takes attention off them.
Because jealousy is accompanied by a sense of inadequacy, it is hard to bear, says Stosny, and most people convert the discomfort into anger, which they regulate by trying to control a partner—distrusting them, going through their belongings and cell phone call logs, making accusations, behaviors more likely to drive a partner away. The trick is you have to control jealousy within yourself. You have to do something that will make you feel more lovable, because basically you feel unlovable when you're jealous.
 Jealousy is not the guardian of love but more typically its destroyer. It arises in relationships whenever we feel "erased" by a partner's lack of attention. Not to blame the partner for attention to someone else, which is what we usually do, but to look inside oneself. There we will find the source of insecurity that instantly makes the rival seem so superior to us. What's at stake in jealousy, she argues, is nothing less than survival of the sense of self.
from Psychology Today