Numbers 5:28

And when he hath made her to drink the water, then it shall come to pass, that, if she be defiled, and have done trespass against her husband, that the water that causeth the curse shall enter into her, and become bitter, and her belly shall swell, and her thigh shall rot: and the woman shall be a curse among her people.

This is the law of jealousies, when a wife goeth aside to another instead of her husband, and is defiled;