The Two Mrs. Grenvilles by Dominick Dunne (1985)
This novel was inspired by the sensational Woodward murder case of 1955 in which a well-born society figure, William Woodward, was shot by his actress/showgirl wife.
In the novel, showgirl Ann Arden marries wealthy Billy Grenville hoping to be accepted by high society and become the well-bred woman of her fantasies. To do this, she must contend with the disapproval of her patrician mother-in-law, Alice. Ann’s rag-to-riches ascent into New York society comes to a halt when she shoots and kills her husband, claiming she thought he was a burglar. The newspapers call it “the shooting of the century.” Alice has no doubts her son was deliberately killed. The Grenvilles and their high-society friends draw a protective shield across the tragedy, and, as a result, the two Mrs. Grenvilles become bound together in a conspiracy of silence.