From a letter:
Finally, a remark by Christopher Tietjens in Ford Madox Ford’s Parade’s End: that one goes to bed with a woman in order to be able to talk to her. Implication: that turning a woman into a mistress is only a first step; the second step, turning her into a friend, is the one that matters; but being friends with a woman you haven’t slept with is in practice impossible because there is too much unspoken in the air.
That is from Here and Now Letters 2008-2011, by Auster and Coetzee. That excerpt is from the first letter, and I will keep reading.