The production worker was ill and returned home early.
But instead of getting some tender loving care, he found his wife in bed making love to their younger co-worker.
When the 22-year-old man refused to leave, Zhuang Minhai, 29, got angry and attacked him with two choppers, injuring the younger man's arm.
For voluntarily causing grievous hurt on grave and sudden provocation, Zhuang was jailed two months on Monday.
Both men and Zhuang's wife, Ms Lin Liyun, 29, are Chinese nationals working at the same factory.
A district court heard that Zhuang, who was working the night shift, was feeling unwell on April 26 and left at about 8.30pm.
But the production worker returned to find his wife having sex with Mr Zhang Zhiyang on their bed in their rented room at Boon Lay Drive.
Outraged by the sight, Zhuang punched Mr Zhang's back several times and told him to leave the room.
The younger man refused to budge.
Enraged, Zhuang went to the kitchen, armed himself with two choppers and returned.
He swung twice and Mr Zhang avoided the blows.
But on the third swing with both choppers, Zhuang slashed Mr Zhang's right arm.
Mr Zhang then left the flat for the National University Hospital in a taxi.
The landlady returned at 8.55pm and saw blood on the floor.
She also heard a commotion from the couple's room and called the police.
"My tenants are fighting in the unit... I could see a lot of blood at my back door," she told police.
Mr Zhang suffered injuries to his upper right arm, including a fracture and a 8cmlong cut.
He was operated on the next day and stayed in the hospital for two days.
His hand will take about six to nine months to recover and he may require more operations.
Zhuang could have been jailed up to six years or fined up to $10,000, or both.
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