#1: Cicisbeo

Definition:

: the recognized gallant of a married woman in Italy especially in the 18th century

Example:

"It is almost impossible for us northerners to take the cicisbeo seriously. He was a cross between a pet dog and a lady's maid, and was beneath them both." – Charles Edwardes, The Living Age, Vol. 195, 1892

About the Word:

There exists in English such a disparity between the number of words to describe women and men of loose morals that it is perhaps worth resurrecting cicisbeo, in an attempt to balance the scales of fairness just a bit.

Words to describe a woman of questionable moral fiber include strumpet, harlot, trull, quean, callet, light-skirts, minx, succubus, fricatrice, trollop, blowen, floozy (and many, many more). Although cicisbeo more properly refers to the man who is the companion or lover of a woman who is married to someone else, it might be thought of as having some overlap with 'man of loose morals.'

—Ammon Shea