Mishnah/Seder Nashim/Tractate Sotah/Chapter 5/1
When the water examined her, then the water examined him, as it is said “and they came, and they came.” (Exodus 5:22, 5:24. 5:27) When she is forbidden to the husband, so is she forbidden to the lover, as it is said “she became impure, she became impure,” (ibid. 5:27, 5:29) -- [these are the] words of R. Akiva. R. Yehoshua said, thus Zechariah Ben HaKatzav would preach/drash: Rabi says, twice they they say in the parsha “if she is defiled, she is defiled,” once for the husband and once for the lover.