Rumors of imminent divorce regularly filled the capital. Gossip swirled that Joe Kennedy, fearing that a nasty scandal might doom Jack's presidential dreams, had offered the former Miss Bouvier a million dollars to remain Mrs. John F. Kennedy--plus a bonus if Jack brought home a disease.
The above is from page 147 of, "1960 LBJ vs. JFK vs. NIXON - The Epic Campaign That Forged Three Presidencies" by David Pietrusza.