In 1994, Koch married Joan Granlund, with whom he had a son, Wyatt. In 1995, he filed a lawsuit against his former lover, Catherine de Castelbajac , to evict her from his $ million condominium at the Four Seasons Hotel in Boston. He said he had allowed her to move in the previous year so she could attend Simmons College , as he seldom used the apartment. When he tried to end the relationship, de Castelbajac refused to move out and claimed he had broken his promises to her. A jury ruled in Koch's favor after a trial that was noted for its disclosure of torrid letters and faxes between the two.