The film Moulin Rouge is set in the night club district of Paris, called Montmartre. The opening scene of Moulin Rouge captures so powerfully what relationship is all about.

Ewan McGregor playing the part of Christian has been jilted by his lover, Satine played by Nicole Kidman.

He got drunk and is now awake and sober. He is dishevelled and unkempt. He feels a great emptiness, a great pain deep down. He is alone in his flat. He sits at his desk and slowly types,
“The greatest thing in all the world is just to love and be loved in return.”
In the depth of despair, he comes up with a great truth.
Man was made for relationship.
Without it he is incomplete.
He has an emptiness that only relationship can fill.
Many, if not all, have felt this loneliness at some time in their lives.