ALLENTOWN, Pa. – A Republican congressman accused of abusing his ex-mistress agreed to pay her about $500,000 in a settlement last year that contained a powerful incentive for her to keep quiet until after Election Day, a person familiar with the terms of the deal told The Associated Press.

Rep. Don Sherwood [pictured left] is locked in a tight re-election race against a Democratic opponent who has seized on the four-term congressman’s relationship with the woman. While Sherwood acknowledged the woman was his mistress, he denied abusing her and said that he had settled her $5.5 million lawsuit on confidential terms.

The settlement, reached in November 2005, called for Cynthia Ore to be paid in installments, according to a person who spoke on condition of anonymity because the deal is confidential. She has received less than half the money so far, and will not get the rest until after the Nov. 7 election, the person said Thursday.

A confidentiality clause requires Ore to forfeit some of the money if she talks publicly about the case, according to this person and two other people familiar with elements of the case.

It is common in settlements for payments to be made in installments and for the parties to be held to confidentiality.

Sherwood admitted no wrongdoing, a standard provision in such agreements, this person said.

Sherwood, a 65-year-old married father of three who is considered a family-values conservative, had one of the safest seats in Congress until Ore sued him in June 2005, alleging he physically abused her throughout their five-year affair.

Reached by telephone Wednesday, the congressman and successful car dealer said: “I can neither confirm nor deny because this was a private settlement. If I’d like to talk to you about it, I can’t.”

The Associated Press has been trying for months to find out the terms of the settlement.

According to a police report, Ore called 911 on her cell phone from the bathroom of Sherwood’s Capitol Hill apartment in 2004 and reported that Sherwood had choked her while giving her a back rub. Sherwood admitted having an affair with the woman, but vehemently denied ever hurting her, and criminal charges were never filed. But Ore, now 30, sued for damages.

Sherwood’s challenger, Chris Carney, has hammered the congressman over the affair in TV ads, calling Sherwood a hypocrite who brought “Washington values” to his rural northeastern Pennsylvania district.

Sherwood responded with his own ad, in which he looked directly into the camera and apologized for his conduct. Last month, his wife mailed a letter to voters that accused Carney of “needlessly cruel” campaign tactics.

Although GOP voters greatly outnumber Democrats in his conservative district, many people have said they would not vote for him again because of the affair.

Even before Ore settled, the congressman tried to keep a tight lid on the case. His lawyer asked a judge to prohibit disclosure of materials from the case, warning that Sherwood’s opponents might try to use the information to harm him politically.

The lawyer, Bobby Burchfield, was especially adamant that any videotaped deposition of Sherwood not be released, saying the footage could be used against him in negative political ads.

Ore’s attorney, Ning Ye of New York, declined to say where she is living now or how she can be reached.