have an affair vs philander

have an affair

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

philander

verb
  • To woo women; to play the male flirt. 

noun
  • A lover. 

  • A South American opossum, bare-tailed woolly opossum, Caluromys philander, formerly Didelphis philander. 

  • An Australian bandicoot, greater bilby or bilby, Macrotis lagotis, formerly Perameles lagotis. 

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