Numbers 5:29

This [is] the law of jealousies
Which was appointed by God to deter wives from adultery, and preserve the people of Israel, the worshippers of him, from having a spurious brood among them; and to keep husbands from being cruel to their wives they might be jealous of, and to protect virtue and innocence, and to detect lewdness committed in the most secret manner; whereby God gave proof of his omniscience, that he had knowledge of the most private acts of uncleanness, and was the avenger of all such. The reasons why such a law was not made equally in favour of women, as of men, are supposed to be these: because of the greater authority of the man over the woman, which would seem to be lessened, if such a power was granted her; because marriage was not so much hurt, or so much damage came to families by the adultery of men, as of women; because women are more apt to be suspicious than men, and in those times more prone to adultery, through their eager desire of children, that they might not lie under reproach {o}:

when a wife goeth aside [to another] instead of her husband, and is
defiled;
is suspected of going aside to another man, and is supposed to be defiled by him.