What lesson does Kristy learn about her husband's death in Chapter 10, and how does she learn that lesson?

Kristy was at the funeral home in Sacramento. She and Summer were alone in the room with Jessie's open casket. Kristy had two hours to think about her husband as she looked at him laying in his casket. She thought about who Jessie was before the war and when she met him. She remembers talking to him and falling in love. That was the lesson she learned: she had married a wonderful man.