
Spoiler???
Although nachan cheats i think its because of his crush on black hair dude and though he does like arata he still had eyes for the other dude and he cheats but later on he realizes he fucked up and arata confronts the black hair dude finds out some shit (i think he was digusted by black hair dude???? Idk man) and he goes back home to a broken and very sorry Nachan but arata understands and they get together again but this time for good and hopefully forever.
Im not a fan of cheating but in instances people dont have clear minds and battle with that which results in shitty ass decisions but if u love someone you can forgive them or let them go. All on you tbh
Its clear hes very devoted in clear emotion but those are some real disturbing ways to do it. If hes adraid u stop son... but whatever im no novelist though ive met some and most are a bit insane