Only women undergo the #sotah trial for suspected adultery. If a man "goes aside" it might be sin (fornication), but it's not adultery by biblical definitions. The concept of adultery in Torah is limited to a woman having relations with someone who is not her husband. The sin in Numbers 5:12 is against the husband because he has a property right in his wife's sexuality. Yeah, yeah...how awful. Don't forget she has a property right in his sexuality too, even if it's of a different nature.

(Yeshua expanded the concept of adultery to a man who divorces his wife unjustly, in part because he has defiled his marriage by treating his wife hatefully, but also, I'm sure, because she would likely need to remarry to avoid poverty.)