Article continues below advertisementMary Richardson Kennedy was heartbroken to watch her kids with Robert F. Kennedy Jr. be "swept up by" his then-girlfriend Cheryl Hines, according to a new book. In Isabel Vincent's new biography, RFK Jr.: The Fall and Rise, she revealed the estranged couple's four children were quick to bond with the Curb Your Enthusiasm star amid their ugly divorce. A friend of Mary's told the author that RFK Jr.