Sotah 28A

דאי אית ביה עון בדקי ליה מיא, כי אית ביה עון בדידיה מי בדקי לה מיא לדידה? והא תניא: ״ונקה האיש מעון והאשה ההיא תשא את עונה״. בזמן שהאיש מנוקה מעון ⁠— המים בודקין את אשתו, אין האיש מנוקה מעון ⁠— אין המים בודקין את אשתו!

that if he has committed a similar iniquity the water evaluates his actions, this is difficult, as in a case where he has committed a similar iniquity does the water even evaluate her fidelity? But isn’t it taught in a baraita that the verse: “And the man should be clear from iniquity, and that woman should bear her iniquity” (Numbers 5:31), indicates that only when the man is clear of iniquity does the water evaluate the fidelity of his wife, but if the man is not clear of iniquity the water does not evaluate the fidelity of his wife?

ואלא לבועל, ליתני כדקתני סיפא: כשם שאסורה לבעל כך אסורה לבועל!

And if the Mishnah is rather referring to the alleged paramour, who is also evaluated by the water that the woman drinks, then let the Mishnah teach as is taught in its latter clause: Just as she is forbidden to her husband, so too is she forbidden to her paramour. Just as there the paramour is mentioned explicitly, so too here, the Mishnah should have stated: Just as the water evaluates whether she was unfaithful, so too, it evaluates whether the paramour committed this iniquity.

לעולם לבועל, ורישא ⁠— איידי דתנא ״אותה״, תני ״אותו״. סיפא ⁠— איידי דתנא ״בעל״, תנא ״בועל״.

The Talmud answers: The entire Mishnah actually does refer to the paramour, and the reason he is not mentioned explicitly in the first clause of the Mishnah is because since it teaches that the water evaluates whether the wife was unfaithful by using the direct object her, it also teaches that the water evaluates whether the paramour committed the act by using the direct object him, without mentioning the paramour explicitly. In the latter clause of the Mishnah, on the other hand, since it teaches explicitly that the woman is forbidden to her husband, it also teaches explicitly that she is forbidden to her paramour.