In her book A Twist of Lennon, Cynthia says that, prior to receiving John's harangue about all of his infidelities, she had been unaware of them; "Discretion must have been John's middle name," she says. Cynthia says that John had given her "grounds for jealousy" only once -- at a private party at which the Magical Mystery Tour movie was shown. On that occasion, John "made a beeline" for a particularly sexy-looking Patti Boyd. A friend of Cynthia's named Lulu was disgusted by this; she cornered John and lectured him. "It was a lovely sight," Cynthia recalled.

Lulu, incidentally, was the singer/actress who starred in To Sir, With Love. She was 19 years of age at the time of the party described by Cynthia.