The spurned lover flew into a fit of rage when he came home to find his fiancée having sex with his friend.
He grabbed his best man in a stranglehold until he passed out. He then kicked and struck him repeatedly in the head, newspaper VG reports.
Once he had regained consciousness, the best man fled the building. Although he was left needing ten stitches to his forehead, he refused to press charges, saying he had deserved a beating for sleeping with his friend’s wife-to-be.
But despite the best man’s reluctance, police ensured that the case went to trial due to the seriousness of the attack.
The district court in Dalane, south-western Norway, sentenced the assailant to 75 days in prison.
The court also fined the best man 5,000 kroner ($860) for failing to show up as a witness at the trial.
“Considering the bride herself said everything was her fault and the best man didn’t want him to be punished, I think the case was harshly judged,” the defendant’s lawyer, Asbjørn Stokkeland, told VG.
“My client is disappointed but he doesn’t intend to appeal.”
After five years as an item, the couple went into counselling to try to rescue their relationship but soon decided the damage was irreparable and split up.