have an affair vs romp

have an affair

verb
  • To engage in a romantic or sexual relationship while being married. 

romp

verb
  • To engage in playful or boisterous sex. 

  • To play about roughly, energetically or boisterously. 

  • (Often used with down) To press forcefully, to encourage vehemently, to oppress. 

  • To win easily. 

  • To move with little effort relatively quickly. 

noun
  • An enjoyable, fast-paced but essentially inconsequential film, play, or other piece of entertainment. 

  • A decisive victory; a game, match etc. which is won easily. 

  • A period of boisterous play, a frolic; now especially, a bout of sexual activity, especially when illicit. 

How often have the words have an affair and romp occurred in a corpus of books? (source: Google Ngram Viewer )