Job 31:10 New English Translation

¹⁰then let my wife turn the millstone^[a] for another man,
and may other men commit adultery with her.^[b]

Job 31:10 tn Targum Job interpreted the verb טָחַן (takhan, “grind”) in a sexual sense, and this has influenced other versions and commentaries. But the literal sense fits well in this line. The idea is that she would be a slave for someone else (or someone else’s wife). The second line of the verse then might build on this to explain what kind of a slave—a concubine (see A. B. Davidson, Job, 215).
Job 31:10 tn Heb “kneel down over her,” an idiom for sexual relations.sn The idea is that if Job were guilty of adultery it would be an offense against the other woman’s husband, and so by talionic justice another man’s adultery with Job’s wife would be an offense against him. He is not wishing something on his wife; rather, he is simply looking at what would be offenses in kind.

New English Translation (NET)