妻 shows a woman 女 with a hand and hair ornament above — one old reading sees a hand pinning up the bride's hair, the coming-of-age gesture of marriage. The character records a wedding in one glyph.
妻子 (qīzi) is the standard word for wife. Classical pairs survive: 夫妻 husband-and-wife, as in 夫妻店 — a tiny shop run by a couple. The legal term is 妻, the affectionate one is 老婆, and the Beijing-polite one is 爱人 'beloved person'.
A woman 女 with her hair being pinned up — the wedding gesture, the WIFE.
夫妻肺片 'husband-and-wife lung slices' is a famous Sichuan dish named for the couple who perfected it in the 1930s — no lungs in the modern recipe, just their marriage in the name.