Śrīmad Bhāgavatam 3.14.19
O respectful one, a wife is so helpful that she is called the better half of a man’s body because of her sharing in all auspicious activities. A man can move without anxiety entrusting all responsibilities to his wife.
By the Vedic injunction, the wife is accepted as the better half of a man’s body because she is supposed to be responsible for discharging half of the duties of the husband. A family man has a responsibility to perform five kinds of sacrifices, called pañca-yajña, in order to get relief from all kinds of unavoidable sinful reaction incurred in the course of his affairs. When a man becomes qualitatively like the cats and dogs, he forgets his duties in cultivating spiritual values, and thus he accepts his wife as a sense gratificatory agency. When the wife is accepted as a sense gratificatory agency, personal beauty is the main consideration, and as soon as there is a break in personal sense gratification, there is disruption or divorce. But when husband and wife aim at spiritual advancement by mutual cooperation, there is no consideration of personal beauty or the disruption of so-called love. In the material world there is no question of love. Marriage is actually a duty performed in mutual cooperation as directed in the authoritative scriptures for spiritual advancement. Therefore marriage is essential in order to avoid the life of cats and dogs, who are not meant for spiritual enlightenment.