" Once married, the woman was supposed to let down her sexual barriers, but this put new pressures on wives. The nineteenth-century focus on female purity had inhibited sexual openness between husband and wife, but it had also accorded women a high moral stature that made it difficult for a man to insist on sex if his wife was unwilling. The twentieth-century preoccupation with the orgasm, by contrast, entitled a woman to more sexual consideration in lovemaking but increased the pressure on her to have sex whenever it was suggested. "

― Stephanie Coontz , Marriage, a History: From Obedience to Intimacy or How Love Conquered Marriage