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.
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.
Greed, desire, ambition, jealousy, possessiveness, domination - you have to watch everything. And they are all interconnected, remember. If greed disappears, then anger will disappear. If anger disappears, jealousy will disappear. If jealousy disappears, violence will disappear. If violence disappears, possessiveness will disappear. They are all intertwined. In fact, they are spokes of the same wheel, and the hub that supports them all is the ego. So watch the ways of the ego.
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.