Jealousy can be triggered by heaps of factors, but we can see why it's common in relationships settings. Threat will often come from a third party and it can make someone feel as if they're being replaced. Some people are more prone to jealousy than others. Psychological factors that lead to a jealous personality type may include low self-esteem which we talked about. A sense of inadequacy is often a cause of jealousy that isn't relationship dependent. People who feel inadequate don't present their sense of personal impotence in relationships alone.