וְאִ֗ישׁ אֲשֶׁ֤ר יִנְאַף֙ אֶת־אֵ֣שֶׁת אִ֔ישׁ אֲשֶׁ֥ר יִנְאַ֖ף אֶת־אֵ֣שֶׁת רֵעֵ֑הוּ מֽוֹת־יוּמַ֥ת הַנֹּאֵ֖ף וְהַנֹּאָֽפֶת׃
Si un homme commet un adultère avec la femme d’un autre homme, avec la femme de son prochain, l’homme et la femme adultères doivent être mis à mort.
Shenei Luchot HaBerit
מות יומת הנואף והנואפת . The reason why both adulterer and adulteress are to be executed by suffocation (20,10), a relatively easy death penalty, may be connected to what the Torah writes elsewhere concerning the type of death penalty to be administered to a murderer. For a person who murdered another with one single stroke (or bullet causing instant death), the Torah legislated death by suffocation; he presumably did not make his victim suffer. There is no reason therefore to impose a harsher type of execution on the adulterer.