wife, spouse
妻 centers on a married woman in relation to her partner: a wife or spouse.
妻 originally depicted a hand (represented by the upper part) seizing a woman (女), reflecting an ancient practice of marriage by capture. The modern form retains the woman radical at the bottom, while the upper part has been stylized.
The bottom is 女 (woman). The upper part looks like a hand reaching down to take a bride. Picture a hand taking a woman as a wife.
For サイ, imagine a wife sighing with contentment: sigh -> サイ, as she settles into married life.
wife
lightning; flash of lightning; lightning bolt
married woman
husband and wife; married couple
wife and children
young wife
new wife
first wife; legal wife
ex-wife; former wife; previous wife
beloved wife
polygamy; polygyny
second wife
legal wife; lawful wife
having a wife; marrying (a woman); marriage
former wife; late wife
good wife
good wife and wise mother
gable
one's legal wife
bad wife