Missouri Governor Eric Greitens, who is facing impeachment over an extramarital affair and a campaign finance inquiry, has announced he will quit on Friday.
The married governor was considered a rising Republican star until allegations emerged he had photographed a naked woman without her consent.
The former Navy Seal previously dismissed the allegations as a “political witch hunt”.
Mr Greitens, 44, was charged in February with invasion of privacy.
The indictment came after a man secretly recorded his wife admitting to having an affair with Mr Greitens in March 2015.
The woman, who was the governor’s hairdresser, alleged that Mr Greitens took a photo of her when she was partially nude without her permission.
He allegedly threatened to release the images if she ever told anyone about the affair.
“I have not broken any laws,” he said at Tuesday’s news conference.
“The last few months have been incredibly difficult,” he said. “This ordeal has been designed to cause an incredible amount of strain on my family.”
He concluded: “For the moment let us walk off the battlefield with our heads held high.
“We have a good and proud story to tell our children.”
A court ruling added to Mr Greitens’ problems earlier on Tuesday.
Cole County Circuit Judge Jon Beetem gave the governor’s political non-profit group, New Missouri Inc, until Friday to turn over communications between it and Mr Greitens’ office.
Investigators are looking into whether his campaign illegally co-ordinated with New Missouri Inc to conceal donors by using shell companies to funnel money.
According to the Kansas City Star, Mr Greitens recieved $6m (£4.5m) in “dark money” for his 2016 campaign.