(NEWSER) – The year before John F. Kennedy was assassinated, Jacqueline Kennedy was determined to divorce him, according to a bombshell new unauthorizedbiography that's making some pretty explosive claims, as per the Daily Mail. Jackie had, supposedly, told her mother back in 1956, "I just can’t see myself spending the rest of my life with Jack Kennedy. It’s not going to happen." By 1962, Marilyn Monroe's sexy "Happy Birthday" performance for JFK embarrassed Jackie and was the final straw, according to Jacqueline Kennedy Onassis: A Life Beyond Her Wildest Dreams, which claims Jackie's early diaries as one of its sources. The book also delves into her alleged affair with Bobby Kennedy, and, amusingly, notes that early in her relationship with JFK, she complained of his "funny body, skinny, with toothpick legs."