12/11/1997 AT 12:00 AM EST
Former Speaker of the House Newt Gingrich and his wife of 18 years, Marianne, were officially divorced on Thursday. They had been separated since May. Attorneys for Gingrich, 56, have admitted that his extramarital relationship with former congressional aide Callista Bisek, 33, started in 1993. This was Gingrich's second marriage.