SINGAPORE - A married businessman was sentenced to a month in jail after he unlawfully wed another much younger woman in Las Vegas.

Ronnie Oh Yin Yan, 58, who is the director of three Singapore-based businesses including tent rental company Sin Hiap Mui, pleaded guilty on Wednesday (May 22) to "purporting to contract a marriage" with the 26-year-old woman in the United States.

The marriage is now void.

Oh legally married his Singaporean wife, now 56, on Oct 20, 1987. The Straits Times understands that they are still together.

He befriended the younger woman online in April 2016 and the pair started a romantic relationship four months later.

Deputy Public Prosecutor Ben Mathias Tan said Oh paid the woman a monthly sum to work in his company and for companionship.

He later told her that he would increase her monthly allowance if she married him.

Court documents did not reveal the amount he was giving her.

The woman accepted his proposal and he suggested tying the knot in the gambling hub of Las Vegas.

The couple registered their marriage on March 28 last year.

Court documents did not state if the woman knew that Oh was already married.

They also did not reveal how the offence came to light but the court heard that Oh admitted to it during an investigation.

Oh, who was unrepresented, told the court on Wednesday that he quarrels with his legally married wife every day.

He also said he is now on medication to treat various ailments, including high blood pressure.

Oh could have been jailed for up to seven years and fined for committing the offence.