Jealousy is an emotion that almost everyone in a relationship experiences from time to time. Persistent feelings of jealousy can damage a relationship and can prove difficult for both parties, particularly if the feelings are irrational or have no basis in reality. The BBC's article, "Understanding jealousy," points out that this complex reaction occurs because it involves a wide array of thoughts, emotions and behaviors. Feelings of jealousy are usually rooted in three main causes-insecurity, fear and competition.

Feelings of insecurity usually arise when one member of the relationship questions the feelings of the other. Insecurity often has roots in low self-esteem but can also stem from a lack of attention from one's partner. If one partner has low self-esteem or little self-confidence, feelings of jealousy become easily triggered by seemingly harmless stimuli, such as one's partner talking to a member of the opposite sex or glancing at someone who passes by on the street. People who compare themselves to others or constantly try to live up to unrealistic expectations of themselves may find these feelings arise frequently.

The fear of losing one's partner remains a main trigger for feelings of jealousy. The BBC's article points out that sometimes feelings of jealousy can prove natural and can encourage a couple not to take each other for granted. Having an awareness that one can lose one's partner can actually strengthen the bonds between couples, but not when this feeling of fear becomes obsessive or irrational. People may fear that their partner want to replace them with someone "better" or more desirable. Providing or seeking reassurance can help to assuage some of these fears.

Feelings of competition are normal human emotions from which jealousy can stem when felt on an extreme level. An article by James Park of the University of Minnesota points out that many people suffering from jealous feelings waste energy trying to be better than others instead of trying to be their "best" self by becoming unique individuals. They may constantly compete with others and they may view anyone as a potential threat. Competitiveness can sometimes help one to do one's best, but can result in constantly questioning oneself, wondering what others have that they don't.