San Francisco Mayor Gavin Newsom will personally pay a former top aide's salary to avoid ethics concerns, his campaign said late Wednesday.

Alex Tourk, 39, resigned as the mayor's re-election campaign manager last week after confronting Newsom about his affair with Tourk's wife, Ruby Rippey-Tourk, 34, when she worked as his appointments secretary.

Newsom quickly agreed to keep Tourk on the campaign payroll, at a rate of $15,000 a month, until he found another job or until his employment contract expired after the November election. But the decision prompted criticism by some city officials who questioned whether it violated campaign finance laws.

"When contributors give money to a candidate, they have a reasonable expectation that candidate's going to use that money to get elected," said John St. Croix, executive director of the San Francisco Ethics Commission who contacted Newsom's campaign about the concerns.

After researching campaign finance law for several days, Newsom attorney Jim Sutton issued a statement Wednesday announcing the mayor's decision to pay Tourk out of his own pocket.

"Because the campaign laws on this are so unclear, the mayor decided the simplest and most appropriate thing to do was for him to personally pay any remaining salary to Alex Tourk until he gets a job," Sutton said.

No confidentiality agreement was attached to the salary arrangement, Sutton added.

Tourk's spokesman, Sam Singer, told KTVU-TV that Tourk accepted the offer, but likely would not need the payments for long because he's been fielding numerous job offers.

"Alex worked very hard for the mayor, was very loyal to him, had no part obviously in what happened," Singer said. "He's got a 3-year-old son to take care of, a mortgage and a wife. So he needs to have this payment until he finds his next job."