Be self-indulgent, and those who are also self-indulgent will like you. Tear your neighbor to pieces, and the other neighbors will laugh. But if you … - Jean-Paul Sartre

It was true, I had always realized it — I hadn’t any “right” to exist at all. I had appeared by chance, I existed like a stone, a plant, a microbe. I could feel nothing to myself but an inconsequential buzzing. I was thinking…that here we are eating and drinking, to preserve our precious existence, and that there’s nothing, nothing, absolutely no reason for existing.

Aujourd'hui encore, je ne puis voir sans plaisir un enfant trop sérieux parler gravement, tendrement à sa mère enfant; j'aime ces douces amitiés sauvages qui naissent loin des hommes et contre eux.
Je regarde longuement ces couples puérils et puis je me rappelle que je suis un homme et je détourne la tête.

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.