Love shouldn't be about jealousy or anything like that. It should be about commitment and being able to trust that person. If you can't have that from the get-go, there's a problem.
Whether we consider the individual, family, local, national or international level, peace must arise from inner peace. For example, making prayers for peace while continuing to harbor anger is futile. Training the mind and overcoming your anger is much more effective than mere prayer. Anger, hatred and jealousy never solve problems, only affection, concern and respect can do that.
Jealousy is comparison. And we have been taught to compare, we have been conditioned to compare, always compare. Somebody else has a better house, somebody else has a more beautiful body, somebody else has more money, somebody else has a more charismatic personality. Compare, go on comparing yourself with everybody else you pass by, and great jealousy will be the outcome; it is the by-product of the conditioning for comparison.
Jealousy in romance is like salt in food. A little can enhance the savor, but too much can spoil the pleasure and, under certain circumstances, can be life-threatening.