The Collaborative International Dictionary of English v.0.48:
Postnuptial \Post*nup"tial\, a. [Pref. post- + nuptial.] Being or happening after marriage; as, a postnuptial settlement on a wife. --Kent. [1913 Webster] Post-obitWordNet (r) 3.0 (2006):
postnuptial adj 1: relating to events after a marriage [ant: antenuptial, premarital, prenuptial]