Extra-marital affair (5)
(Other definitions for amour that I've seen before include "(Illicit) sexual relationship" , "close relationship" , "French romance" , "Affair of the heart" , "French lover" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">extra-marital affair</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for adultery that I've seen before include "Betrayal of a partner" , "Extramarital sex" , "Extramarital bedroom antics" , "excluding union involvement?" , "cheating" .)