Yuichiro Tamaki, a kingmaker for Japan’s minority government, will temporarily step down as his party’s leader amid a scandal over an alleged marital infidelity.

Motohisa Furukawa, the party’s tax chief, will take the leadership role of the Democratic Party for the People for the next three months, with Tamaki set to return as party leader on March 4, according to DPP Secretary-General Kazuya Shimba.

ALSO READ: Head of key Japan opposition party admits extra-marital affair

The DPP decided to punish Tamaki over the scandal, which was reported last month hours before Japan’s parliament reinstalled Shigeru Ishiba as premier while the DPP nominated Tamaki for its top job.

“I have damaged the honor and trust of the party,” Tamaki said Wednesday following the decision. “I take this very seriously and I intend to deal with this matter sincerely.”

The opposition party has become a power broker following the loss of the ruling coalition’s majority in October’s election. By year-end, it’s expected to strike a deal with the ruling coalition over how high to lift the ceiling for tax-free income from the current 1.03 million yen ($6,900) as part of tax reforms for next fiscal year.

READ MORE: Japan govt approves 13.9t yen extra budget to fund stimulus package

That’s the DPP’s top policy agenda and it wants the ceiling to be raised to 1.78 million yen to make it more lucrative for part-time workers to put in more hours, a step that’s seen spurring consumption. The government expects doing so would result in a tax loss of up to 8 trillion yen.