1 Corinthians 7:3,4 - Joseph Benson’s Commentary on the Old and New Testaments

Let the husband Where this relation is commenced; render unto the wife, Την οφειλομενην ευνοιαν, the due benevolence That is, the conjugal duty, the duty resulting from the nature of the marriage- covenant. Or, let not married persons fancy that there is any perfection in living with each other as if they were unmarried. The wife hath not power over her own body Namely, in this respect, but by the marriage- covenant hath transferred it to her husband. And likewise the husband hath not power over his own body; but it is, as it were, the property of the wife, their engagements being mutual; so that, on every occasion, conscience obliges them to remain appropriated to each other. “The right of the wife to her husband's body, being here represented as precisely the same with the husband's right to her body, it excludes the husband from simultaneous polygamy; otherwise the right of the husband to his wife's body would not exclude her from being married to another, during her husband's lifetime. Besides, the direction, (1 Corinthians 7:2,) let every woman have her own husband, plainly leads to the same conclusion. The right of the wife to her husband's body is a perfect right, being founded on the ends of marriage, namely, the procreation of children, their proper education, and the prevention of fornication. But these ends would, in a great measure, be frustrated, if the wife had not an exclusive right to her husband's person.” Macknight.