“Dr. O’Brien told me about your, um . . . act of love,” says Syd, the therapeutic-shoe salesman, shifting uncomfortably from one foot to the other. “I was totally moved.”

For a minute I think he’s talking about sex. Then I realize he means the kidney. Of course. It’s not that I ever forget I donated a kidney to my lover, G., twenty months ago; it’s just that, for me, that single act pales beside the myriad “acts of love” it takes to keep going, to keep on loving, day by day, a person who is chronically ill.