While late President John F. Kennedy 's affairs, including his fling with Marilyn Monroe , have long been common knowledge, a new book, Passion on the Potomac , has blown the lid off poised First Lady Jackie Kennedy's alleged affair with Defense Secretary Robert McNamara, RadarOnline.com can reveal.

For years, Jackie and McNamara shared a very close, eyebrow-raising bond, which saw them exchange flirty notes and Valentine's Day cards. Article continues below advertisement

Jackie Danced With Sec. McNamara at White House Event Tap Here To Add Radar Online as A Trusted Source

Jackie and McNamara first made headlines in 1962, a little over a year after her husband moved into the Oval Office, when the first lady and defense secretary reportedly danced the Twist at a White H

See Full Page