adulterous adulterous /əˈdʌltərəs/

adjective

1. Not faithful to a spouse or lover  ( adulterous , cheating , two-timing )
   not faithful to a spouse or lover
    Adulterous husbands and wives
   adulterous husbands and wives
    A two-timing boyfriend
   a two-timing boyfriend
   
2. Characterized by adultery  ( adulterous , extracurricular , extramarital )
   characterized by adultery
    An adulterous relationship
   an adulterous relationship
    Extramarital affairs
   extramarital affairs
    The extracurricular activities of a philandering husband
   the extracurricular activities of a philandering husband