"What we have is an essential love; but it is a good idea for us also to experience contingent love affairs."

So wrote Jean Paul Sartre to Simone de Beauvoir, who agreed to the arrangement. (Via A&L Daily.) She wrote:

"We were two of a kind, and our relationship would endure as long as we did: but it could not make up entirely for the fleeting riches to be had from encounters with different people."

Can a deal like this work? Would it help if you were a couple of geniuses like Jean Paul and Simone? Well, even for them, it fell short:

It was he who engaged in countless affairs, to which she responded on only a few occasions with longer-lasting passions of her own. Between the lines of her fiction and what are in effect six volumes of autobiography, it is also evident that De Beauvoir suffered deeply from jealousy. She wanted to keep the image of a model life intact. There were no children. They never shared a house and their sexual relations were more or less over by the end of the war, though for much of their life and certainly at the last, they saw each other daily.

With the posthumous publication in 1988 of her letters to Sartre, a good proportion of them written during the war years when he was at the front and then a prisoner, gaps that were left out of the autobiography are filled in. What the letters express is not only De Beauvoir's overarching love for a man who is never sexually faithful to her, a man she addresses as her "dear little being" and whose work she loyally edits. They also underline the mundanity of De Beauvoir's early accommodation to his wishes, her acceptance of what many women would reject as demeaning, her dependence.