Spouse
Middle English: from Old French spous(e ), variant of espous(e ), from Latin sponsus (masculine), sponsa (feminine), past participles of spondere ‘betroth’.
wiktionary
From Middle English spous, spouse, from Anglo-Norman espusm, espusef and Old French esposm, esposef and by aphesis from Latin spōnsusm(“bridegroom”), spōnsaf(“bride”), from spondeō(“I vow, pledge”), from Proto-Indo-European *spend-.
Cognate to espouse, sponsor.
etymonline
spouse (n.)
c. 1200, "a married person, either one of a married pair, but especially a married woman in relation to her husband," also "Christ or God as the spiritual husband of the soul, the church, etc.," also "marriage, the wedded state," from Old French spous (fem. spouse) "marriage partner," variant of espous/espouse (Modern French épous/épouse), from Latin sponsus "bridegroom" (fem. sponsa "bride"), literally "betrothed," from masc. and fem. past participle of spondere "to bind oneself, promise solemnly," from PIE *spend- "to make an offering, perform a rite" (see sponsor (n.)). Spouse-breach (early 13c.) was an old name for "adultery."
