word-forming element meaning "before," from Old French pre- and Medieval Latin pre-, both from Latin prae (adverb and preposition) "before in time or place," from PIE *peri- (source also of Oscan prai, Umbrian pre, Sanskrit pare "thereupon," Greek parai "at," Gaulish are- "at, before," Lithuanian prie "at," Old Church Slavonic pri "at," Gothic faura, Old English fore "before"), extended form of root *per- (1) "forward," hence "beyond, in front of, before."
The Latin word was active in forming verbs. Also see prae-. Sometimes in Middle English muddled with words in pro- or per-.
"of or pertaining to a husband, or to marriage as it pertains to the husband," hence, more broadly, "pertaining to or relating to marriage, matrimonial," c. 1600, from French maritale and directly from Latin maritalis "of or belonging to married people," from maritus "married man, husband," which is of uncertain origin (see marry (v.)).
<a href="https://www.etymonline.com/word/premarital">Etymology of premarital by etymonline</a>
Harper, D. (n.d.). Etymology of premarital. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/premarital