Divorce rates in long-term marriages have risen significantly in recent decades. It is not primarily young people who are getting divorced, but rather middle-aged men and women—those between the ages of 45 and 65. Why do so many decades-long partnerships break apart? Are late divorces crises that open the door to a good new beginning, or are they rather the start of chronic suffering? We know surprisingly little about this, as scientific research has focused almost exclusively on divorces involving couples with underage children until recently. This book aims to fill that knowledge gap. It first discusses the changes and significance of marriage over the centuries. It is shown that regardless of the historical period, the fact remains that intimate relationships are existentially important for well-being and health and continue to be sought after.