SINGAPORE - A man who returned home from a night of drinking found himself locked out of the flat he shared with his girlfriend and uncle - and suspected they were having an affair.

When Teh Wah Leng got into their home, he punched Mr Ong Chin Hua, 65, in the face, kicked him in the chest and beat him with a metal chair. He even pulled out a fruit knife and challenged his relative to stab him.

Teh, 45, was sentenced him to nine months in jail for voluntarily causing hurt to Mr Ong, who suffered a broken jaw and hand.

"There is no justification for such behaviour," District Judge Kenneth Yap told the court on Wednesday (May 23).

Deputy Public Prosecutor Dwayne Lum said that on Jan 13 last year, Teh returned home at about 5am after drinking alcohol.

Upon finding the main door locked, he grew suspicious that Mr Ong and his girlfriend, Ms Kong Lijin Teresa, 40, were having an affair, an allegation which the DPP described as "entirely false".

Teh entered the apartment, grabbed a knife, and headed for Mr Ong's bedroom, where he punched him in the face repeatedly, causing him to bleed around his left eye.

Mr Ong walked to the toilet but Teh followed him in and threw a pail at him.

The older man then went to the living room, where Teh pointed the knife at himself and told Mr Ong to stab him.

After he refused, Teh hit him with a metal chair, and as he lay on the ground, continued to kick him in the chest.

Mr Ong, who works as a consultant in the wellness industry, was taken to Singapore General Hospital, where he was hospitalised for a day.

Teh's blood alcohol level was found to be well over the drink-driving limit, five hours after the offence.

DPP Lum added: "Those who voluntarily imbibe alcohol must... take full responsibility for their subsequent offending.

"The severe pain and suffering endured by the victim served as unwarranted and unnecessary 'payback' for an entirely false allegation.

"There was no opportunity given to the victim to reason with the accused, nor was there any chance for the victim to disengage himself from the situation given the unrelenting and escalating nature of the assault."

Teh, a renovation coordinator, faced another charge of pointing a fruit knife at himself, which was likely to cause alarm, an offence taken into consideration during sentencing.

For voluntarily causing hurt, Teh could have been jailed for up to two years, fined, or both.