Jealousy can be caused by a threat to, or the loss of, a valued relationship due to an actual or imagined rival and is associated with relationship conflict, domestic violence and divorce. It can contribute to relationship insecurity and conflict and cause the non-jealous partner to feel mistrusted and controlled. Other researchers have put a more positive interpretation on jealousy, however, seeing it as a sign that partners care for each other and value their relationship enough to protect it. A study of 961 couples in Holland has found evidence to support both these hypotheses. Couples with high levels of 'reactive' jealousy (jealousy in the face of a real and concrete threat to a relationship) had a higher quality of relationship whereas couple with high levels of 'anxious' jealousy (groundless suspicion in the absence of any evidence) had poorer relationships.
Barelds, D. P. H. and Barelds-Dijkstra, P. - Relations between different types of jealousy and self and partner perceptions of relationship quality Clinical Psychology and Psychotherapy May-June 2007, 14(3), 176-188