Who is Peggy Connover from The Sportswriter and what is their importance?

Frank meets Peggy Connover on a plane shortly after Ralph's death. She is middle-aged, frumpy, and unattractive. Frank, however, finds her a good conversationalist and takes her to dinner. Frank describes Peggy as outgoing, funny, and highly entertaining. The couple, however, does not have an intimate relationship, even though they go onto become good friends. Over the course of the novel, Frank and Peggy exchange letters, something that leads X to file for divorce, as she sees them as proof that her husband finds it easier to confide in total strangers than his wife.