WHAT MAKES US GRIEVE WHEN ANY RELATION DOESNT CONTINUE?
We dont grieve because others matter to us. We grieve because we dont matter to them. Ideally, we should feel happy when others matter to us, because, then we feel happiness in giving. But, we are unhappy when we dont receive, which shows, we should be important to others.
Keep your expectations nill. Feel happy in giving than receiving. Whoever comes or leaves your life, you will never be unhappy.