It answers the question that was tormenting you: my love, you are not 'one thing in my life' - not even the most important - because my life no longer belongs to me because...you are always me.
Jean-Paul SartreNothing happens while you live. The scenery changes, people come in and go out, that's all. There are no beginnings. Days are tacked on to days without rhyme or reason, an interminable, monotonous addition.
Jean-Paul SartreHe walked on in silence, the solitary sound of his footsteps echoing in his head, as in a deserted street, at dawn. His solitude was so complete, beneath a lovely sky as mellow and serene as a good conscience, amid that busy throng, that he was amazed at his own existence; he must be somebody else's nightmare, and whoever it was would certainly awaken soon.
Jean-Paul Sartre