The English word "husband" is one of many gifts of the Vikings. It comes from the Old Norse húsbóndi, a compound of hús ("house") and bóndi ("a free man who farms his own land," from the verb búa, "to dwell"). A húsbóndi was, literally, the "master of the house" — the head of a household, whether or not he was married.
A Norse Borrowing
The word came into Old English through the Viking settlements in the north and east of England, between roughly the 9th and 11th centuries. In its earliest English use, "husband" still meant a head of household or a tenant farmer; the marital sense was only one possible meaning.
From Householder to Spouse
By the late Middle Ages, the marital sense had crowded out the others, and "husband" came to mean specifically a married man — presumably because being head of a household and being married were so often the same thing. The word displaced the earlier Old English wer, "man, husband" — which survived only in the compound werewolf ("man-wolf").
To Husband Resources
The original sense of "household management" survives in the verb form. To husband resources is to manage them prudently, the way a careful householder would. Husbandry, from the same root, is the practice of farming or careful management; animal husbandry is one of the few places the older meaning is still completely alive in everyday English.