Shirley Jackson: A Rather Haunted Life by Ruth Franklin:
More problematic was Stanley’s persistent interest in other women, which he saw no reason to hide. Dowson’s poem about a man who confesses infidelity even as he pines for his lost love—“I have been faithful to thee, Cynara, in my fashion!”—became their personal shorthand. (“My fashion has been acting up again,” Stanley would sometimes say, addressing Shirley as “Cynara,” after he had been out with another woman.) As much as he loved Shirley—and he was already deeply in love with her—Stanley, embracing a self-styled polyamorous philosophy, saw no reason to limit himself to a single woman. He believed he held the moral high ground: open marriage was a Communist principle. His hero John Reed—Stanley recommended Ten Days That Shook the World, Reed’s eyewitness account of the Russian Revolution, to anyone who would listen—was notorious for his affairs. Shirley, too, was welcome to go out with whomever she liked, he asserted rather disingenuously. She would take him up on it only once.