Antenuptial

adj. before marriage

A prenuptial agreement, antenuptial agreement, or premarital agreement, commonly abbreviated to prenup or prenupt, is a contract entered into by two people prior to marriage or civil union. The content of a prenuptial agreement can vary widely, but commonly includes provisions for the division of property should the couple divorce and any rights to spousal support during or after the dissolution of marriage.
See more at Wikipedia.org...

Adjective
1. relating to events before a marriage; "prenuptial agreement"
(synonym) prenuptial, premarital
(pertainym) wedding, wedding ceremony, nuptials, hymeneals

(a.)
Preceding marriage; as, an antenuptial agreement.
  

An event or document which pre-dates a marriage. - (read more on Antenuptial)