(AP) ATLANTA – Georgia's powerful House speaker resigned Thursday after a suicide attempt and allegations by his ex-wife of an affair with a lobbyist.

Glenn Richardson, the state's first GOP speaker since Reconstruction, had won sympathy from even his political enemies when he revealed last month that he attempted suicide by swallowing sleeping pills. But then his ex-wife went on TV and accused him of having "a full-out affair" with a lobbyist while they were still married.

Richardson did not address that allegation in a brief statement issued through the House communications office in which he said he will leave both his position as speaker and his House seat on Jan. 1. He did mention his recent admission, made in the wake of his suicide attempt, that he has grappled with depression.

"I fear that the media attention of this week has deflected this message and done harm to many people who suffer from this condition," he said in the statement.

The 49-year-old once thought to be a serious contender for governor had gone right back to shaking hands at chicken-and-grits fundraisers after trying to kill himself, but he had been silent since his ex-wife claimed this week that he slept with a lobbyist pushing a $300 million pipeline bill he was co-sponsoring.

It has been a dizzying fall for one of Georgia's most powerful political figures. Sheriff's deputies found him Nov. 8, slumped semiconscious on the edge of the bathtub at his west Georgia home after he called his mother to say he had swallowed pills. A suicide note and a silver .357 Magnum were on the counter next to him. The contents of the note have not been released.

Secretary of State Karen Handel, a leading candidate for governor in 2010, called Richardson's personal turmoil "heartbreaking" but said meetings at the state Capitol were grinding to a halt because he was missing in action amid the worst state budget crunch in the state history.

"We have very serious issues that the Legislature needs to deal with that require leadership and focus and it's clear that we don't have either right now," Handel told The Associated Press before Richardson stepped down.

She and the Georgia Christian Coalition were among those who had called Thursday for Richardson to resign.

University of Georgia political science professor Charles Bullock said Richardson is known for comebacks, but the latest round of news may have finally damaged him beyond repair.

"Heading into an election year, I think Republicans would rather not still be talking about the life and loves of Glenn Richardson," Bullock said.

Richardson was revered among some conservatives for helping engineer a GOP takeover of the Georgia House in 2004 after decades of Democratic control. But his short temper has often left him feuding with the state's other leading Republicans. In 2007, a red-faced Richardson accused Gov. Sonny Perdue of showing his "backside" after the two feuded over tax cuts.

He has also been dogged by messy personal and ethical problems, including a 2007 ethics complaint by House Democrats over the same alleged affair ex-wife Susan Richardson accused him of on TV this week. In an interview Monday with Fox 5 Atlanta, Susan Richardson said she had e-mails between her ex-husband and the lobbyist for Atlanta Gas Light that prove the affair. The couple divorced in February 2008.

In one e-mail, according to Fox 5, the lobbyist worried that she would be fired if the affair became public. Glenn Richardson responded by saying he would "bring all hell down" on Atlanta Gas Light if that happened.

The 2007 Democratic complaint was dismissed by a legislative ethics panel for lack of evidence, and a defiant Richardson used a breakfast speech before a room full of Georgia business leaders to threaten retaliation against those he said he said were trying bring him down with "poison."

The bad news, according to Richardson, "is that I survived." And, he continued, "I'm looking for those that manufactured that poison."

The top Democrat in the House, Minority Leader DuBose Porter, said Susan Richardson's allegations should prompt a renewed ethics probe.

Glenn Richardson has not responded to the affair allegations, and a spokesman did not return repeated calls Thursday.