People often ask, Why is infidelity such a big deal today? Why does it hurt so much? How has it become one of the leading causes of divorce? Only by taking a brief trip back in time to look at the changes of love, sex and marriage over the last few centuries can we have an informed conversation about modern infidelity. History and culture have always set the stage for our domestic dramas. In particular, the rise of individualism, the emergence of consumer culture, and the mandate for happiness have transformed matrimony and its adulterous shadow. Affairs are not what they used to be because marriage is not what it used to be.