Definition of "extramarital"

David H. Petraeus, the director of the Central Intelligence Agency and one of America’s most decorated four-star generals, resigned on Friday after an F.B.I. investigation uncovered evidence that he had been involved in an extramarital affair.

2012 November 9, Michael D. Shear, “Petraeus Quits; Evidence of Affair Was Found by F.B.I.”, in New York Times‎