Stress?
Maybe from juggling too many chicks at one time.....
Maybe that’s why Bill was nailing Eleanor Mondale (Walter Mondfale’s 37 year old daughter) in the White House at the same time he was doing Monica.
Just relieving tension.
https://nypost.com/2016/06/18/monica-lewinsky-ironically-freaked-out-that-bill-cheated-on-her/
Or.....
Monica relieved the stress induced by sex with Eleanor
Wow Mondale was a pretty sporty looking gal...