Numbers 5:11-31 gives us an adultery test used by the Hebrew people in their early days.
11 Then the Lord spoke to Moses, saying, 12 “Speak to the sons of Israel and say to them, ‘If any man’s wife goes astray and is unfaithful to him, 13 and a man has intercourse with her and it is hidden from the eyes of her husband and she is undetected, although she has defiled herself, and there is no witness against her and she has not been caught in the act, 14 if a spirit of jealousy comes over him and he is jealous of his wife when she has defiled herself, or if a spirit of jealousy comes over him and he is jealous of his wife when she has not defiled herself, 15 the man shall then bring his wife to the priest, and shall bring as an offering for her one-tenth of an ephah of barley meal; he shall not pour oil on it nor put frankincense on it, for it is a grain offering of jealousy, a grain offering of memorial, a reminder of iniquity.
29 ‘This is the law of jealousy: when a wife, being under the authority of her husband, goes astray and defiles herself, 30 or when a spirit of jealousy comes over a man and he is jealous of his wife, he shall then make the woman stand before the Lord, and the priest shall apply all this law to her. 31 Moreover, the man will be free from guilt, but that woman shall bear her guilt.'"
I think the "man" in v.31 is referring to the adulterous woman's husband. If so, what guilt is the man 'free' from? If all he has is a righteous jealousy for his wife, then why is there any mention of his guilt? If it's not him, then the verse must be talking about the man who committed adultery with this woman. If so, why is he free from guilt?