In the suspected case of an unfaithful wife (Numbers 5:11-31) why is the husband not punished?

Question

In the suspected case of unfaithful wife 'the husband is said to be innocent' even after the wife have been proved to be innocent after under going the test.

Numbers 5:11-15 NIV

11 Then the Lord said to Moses, 12 “Speak to the Israelites and say to them: ‘If a man’s wife goes astray and is unfaithful to him 13 so that another man has sexual relations with her, and this is hidden from her husband and her impurity is undetected (since there is no witness against her and she has not been caught in the act), 14 and if feelings of jealousy come over her husband and he suspects his wife and she is impure—or if he is jealous and suspects her even though she is not impure— 15 then he is to take his wife to the priest. He must also take an offering of a tenth of an ephah[c] of barley flour on her behalf. He must not pour olive oil on it or put incense on it, because it is a grain offering for jealousy, a reminder-offering to draw attention to wrongdoing.

But in a more or less similar situation in the book of Deuteronomy a malicious witness who is proved to be a liar is given the same punishment which he had intended to be given to the other party

Deuteronomy 19:16-19 NIV

16 If a malicious witness takes the stand to accuse someone of a crime, 17 the two people involved in the dispute must stand in the presence of the Lord before the priests and the judges who are in office at the time. 18 The judges must make a thorough investigation, and if the witness proves to be a liar, giving false testimony against a fellow Israelite, 19 then do to the false witness as that witness intended to do to the other party. You must purge the evil from among you.

Why is the husband not punished as a malicious witness?

Answer 1

Kyle gave a good answer already. Here I will supplement a little in terms of legal technicalities.

Deuteronomy 19:

16 If a malicious witness takes the stand to accuse someone of a crime,

Numbers 5:

13 so that another man has sexual relations with her, and this is hidden from her husband and her impurity is undetected (since there is no witness against her and she has not been caught in the act),

1. The husband admittedly was not a witness.

14 and if feelings of jealousy come over her husband and he suspects his wife and she is impure

In legal terms, there is a technical and important difference between suspecting his wife and accusing his wife.

2. The husband did not accuse his wife.

In the suspected case of an unfaithful wife (Numbers 5:11-31) why is the husband not punished?

Because the husband did not accuse his wife of wrongdoing as a witness.

Answer 2

The Numbers text is clear that the husband is not bearing false witness, but is honestly reacting from his actual feelings of jealousy. By the plain reading of the text these are different. But is the spirit the same? No.

Not bearing false witness is one of the ten commandments. To be jealous of your own wife is not; indeed our God is a jealous God. However, only God is so clearsighted as to never think false thoughts. What does God want from the husband with a spirit of jealousy to do? Numbers 5 tells us. There is no room for false witness in this procedure. The husband infected with a spirit of jealousy - even falsely - who initiates this procedure is being obedient to God's command.

This is a very good thing for the woman. (And to the extent that being exposed to the process is a punishment for the woman, having been shown to be falsely jealous is a punishment.) To discourage it - by making the husband pay penance - would therefore not be good for the wife, and since God is love and loves the wife he does not want her harmed. It is not something to do lightly - the barley flour is a real cost - and that is a good thing. But it is better for the marriage, and for love, and for children that the spirit of jealousy should have been expunged. And thus He granted to the Israelites a method for such.

The specific overrules the general, and God has provided a specific way for the husband to react to the spirit of jealousy that leaves no room for false witnessing and strengthens this crucial relationship. And so the husband need not be put to death.