内縁の妻

内縁の妻　= common-law wife

Police said Saturday they have arrested a 34-year-old man and his 20-year-old common-law wife for allegedly abusing the woman’s 2-year-old daughter at their home in Tomisato City, Chiba prefecture.
(Japan Today 2012/06/02)

「警察は土曜日、34歳になる男と20歳の内縁の妻を、女の2歳になる娘を千葉県富里市の自宅で虐待したとして逮捕した。」

★参考
（人）と内縁関係にある 　have de facto marriages with~

★全文記事はこちら
Truck driver, common-law wife arrested for abusing woman's 2-year-old daughter