Some people think that jealousy should be part of the relationship: it is a proof of love, a way to show that the person cares and loves you, and is attentive to the other's life. But love is another thing: love is respect for the other's life, it is to dialogue to understand the decisions of the other, it is to trust each other. Love sustains itself and needs no proof!
People who feel the need to constantly monitor the footsteps of another, control what the other is doing, who they're talking to on the phone, and worst of all, what they think, add unnecessary suffering to their lives. Jealousy is the desire and need to control the other, and it transforms the experience of living as a couple into a never ending suffering.