Source : Webster's Revised Unabridged Dictionary (1913)

Postnuptial \Post*nup"tial\, a. [Pref. post- + nuptial.]
   Being or happening after marriage; as, a postnuptial
   settlement on a wife. --Kent.

Source : WordNet®

postnuptial
     adj : relating to events after a marriage [ant: {prenuptial}]