Sartre and Beauvoir’s bond was intense enough to sadden outsiders who lacked it.

Evidence

With all these differences, they had a mutual understanding that no outsider seemed able to threaten. When Beauvoir’s biographer Deirdre Bair was talking to her subject’s friends, one of them, Colette Audry, summed it up by saying, ‘Theirs was a new kind of relationship, and I had never seen anything like it. I cannot describe what it was like to be present when those two were together. It was so intense that sometimes it made others who saw it sad not to have it.’ — Sarah Bakewell, At the Existentialist Café, 393