Two individuals relating remain individuals; two individuals getting into a relationship lose their individuality. They become a couple, and to be a couple is an ugly thing. That means you have lost your freedom, you are no more yourself; the other is also no more himself or herself. Both have lost their freedom and nobody has gained anything out of it.
That's why Sartre says, "The other is hell." But still I would like to remind you: it is not the other it is the desire for the other. When you have understood the futility of desire, the utter stupidity of desire, then you relate in a totally different way; a qualitative change happens to you. You are happy with yourself; you are not seeking happiness through the other. You are so happy that you would like to share it with somebody, that's why you relate.
Relationship originates in misery, relating originates in bliss.
And when you start relating with people you also start relating with existence.
-Osho, "Walking in Zen Sitting in Zen, #7, Q1"