Jealousy - A strong emotion. An emotion that everyone has experienced in their lifetimes sometime or the other. An emotion that can break strongest of relationships. An emotion that can chew you alive from the inside.
Emotion - an affective state of consciousness in which joy, sorrow, fear, hate, or the like, is experienced, as distinguished from cognitive and volitional states of consciousness.
Emotions are funny things, really. They can make you, or break you. Build you up, or tear you down. They're what makes us human.