mark. they knew something. the wanglere to know the problems went back years. >> kathy had told me mark had an affair. >> that kind of been easy for her sister. >> she could never forgive him for that. >> they managed to carry on. over the years, kathy's family remembers simmering tensions that could erupt into open warfare. they say mark thought kathy gained too much weight. she wouldn't clean the house. she spent huge amounts of money. kathy got mad at mark a lot. diana recalls what happened right after they took this family portrait. mark and kathy were fighting again. >> she got in the car, the points got in the car. mark was hanging on the side of the car. kathy was driving away, yelling at him. at one point, one of the boys jumped out and there was a lot of yelling and carrying on. and then kathy left with the boys. >> mark wangler admits things did go downhill after the boys left for college. he says kathy would get deeply depressed. >> but the boys being gone, she lost her purpose in life, i would say. >> we're wor