Jealousy in a relationship is a fear of losing that person. It's insecurity. The relationship has not been nurtured to where both parties feel secure. A perfectly natural reaction when the relationship is important to the individual.
Whether it be your creativity your business/career your relationships your chapter in life comparison to others will only discourage you and fill you with self-doubt. It doesn't matter what anyone else is doing focus on your own shit give it and allllll of the good things will come. Success is not measured by how you compare it's measured by your happiness! by even.keel