Although we are all the same in not wanting problems and wanting a peaceful life, we tend to create a lot of problems for ourselves. Encountering those problems, anger develops and overwhelms our mind, which leads to violence. A good way to counter this and to work for a more peaceful world is to develop concern for others. Then our anger, jealousy and other destructive emotions will naturally weaken and diminish.
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.
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.