The former business executive, facing a woman's allegation of a 13-year extramarital affair, says a heavy emotional toll on his family - particularly his wife, Gloria, who he has not seen since the charge surfaced - could force him to call it quits. The shift comes as a growing chorus of would-be allies suggests he is no longer a viable presidential contender and Cain himself says fundraising has suffered.
Cain, a top-tier candidate just weeks ago, says he'll decide in the next "few days" whether to abandon his White House bid, but not before he meets with his wife.
"Since I've been campaigning all week, I haven't had an opportunity to sit down with her and walk through this with my wife and my family. I will do that when I get back home on Friday," Cain told reporters gathered at his New Hampshire campaign headquarters Wednesday night. "I am not going to make a decision until after we talk face to face."
Cain said he had spoken to his wife only by phone since Monday, the day an Atlanta television station reported the woman's accusation. Since then, aides have crafted a packed campaign schedule with stops in Ohio, New Hampshire, Tennessee, South Carolina and Georgia and prepared to launch a fresh round of TV ads in Iowa.
Cain talked about Gloria's reaction to the story in an interview with FOX News on Wednesday.
"Yes, she did ask me, and I have told her exactly what has happened and what the situation is," he said. "My wife loves me, she just told me that again today. She just wants to know the truth, which I have given her the truth and she just gets upset when she sees the implications and the distortions by some people in the media."
When asked why White would lie about an affair, Cain told FOX that her announcement was "totally out of the blue," and she is out to destroy his candidacy.
"I have no idea, unless the people who I believe are putting her up to this," he said. "Maybe that was one of the lines that she was supposed to use. I have no idea, I honestly don't."
Cain was to sit down Thursday afternoon with the New Hampshire Union Leader, an influential conservative voice in the first-in-the-nation primary state. This evening the former pizza executive is scheduled to deliver a business-focused speech at Middle Tennessee State University.
"There were some people who thought that I was finished," Cain said Wednesday night. "But I'm going to leave it with Yogi Berra's comment: 'It ain't over till it's over.' And it ain't over yet."
Many Republican operatives believe Cain's bid is over whether he pulls the plug or not.
"I don't see how they walk away from the damage that's been done and emerge as a viable primary candidate," said Rick Wilson, a longtime GOP consultant based in Florida. "All these things about Herman Cain keep coming out drip, drip, drip, and they're not handling it well. And now conservative Republicans have another place to go: Newt Gingrich."
Dan McLagan, a veteran GOP strategist based in Atlanta, said Cain "is like a zombie at this point: He's dead but he does not appear to have noticed and has kept on walking."
"His support is all moving to Gingrich and, at some point, he's going to look back and see that he is grand marshal of a one-man parade," McLagan said.
Gingrich has been the beneficiary - in polls, at least - of Cain's slide in the month since it was disclosed that the National Restaurant Association paid settlements to two women who claimed Cain sexually harassed them while he was its president. A third woman told The Associated Press that Cain made inappropriate sexual advances but that she didn't file a complaint. A fourth woman also stepped forward to accuse Cain of groping her in a car in 1997.
Cain has denied wrongdoing in all cases.
Atlanta-area businesswoman Ginger White, 46, said her affair with Cain ended this year before he became a White House candidate. He has denied any such affair, and in a letter addressed to "patriots and supporters" called her allegations "completely false" and labeled her "troubled."
"It's very disappointing that he would call me troubled and, you know, it's unfortunate," White said Wednesday on ABC's "Good Morning America."
Top aides huddled privately Wednesday to map out a strategy to get past the allegations. He has told his top supporters that his campaign must determine whether he will have the financial and grassroots support to move ahead.
"The day that this latest one hit, fundraising went way down," Cain told reporters in New Hampshire. "As the week has gone on and this woman who has made these accusations has basically started to contradict herself, our fundraising has started to go back up. It's not up to the level where it was, but a lot of people are saying, you know what, they don't believe it."
In New Hampshire and at other campaign stops this week, he renewed what has become a familiar defense: that he is the victim of attacks by liberals and the establishment, who are threatened by his outsider appeal.
"They want you to believe that with another character assassination on me that I will drop out," a defiant Cain told a crowd of about 200 Wednesday in Dayton, Ohio. Some responded with shouts of "No!" and "Boo!"
In Iowa, Cain's state chairman, Steve Grubbs, said he was preparing a busy December schedule beginning with a Dec. 10 debate in Des Moines. And Grubbs said Cain, who has not aired any campaign ads in Iowa since last week, will resume advertising Friday with a new spot that asserts that electing Cain would put a veteran CEO in the White House, not a politician.
"His campaign is strong enough to survive the allegations," said Michael Farren, 31, an Ohio State University doctoral student in economics, from Pataskala, Ohio.
Associated Press writers Shannon McCaffrey in Atlanta, Ann Sanner in Columbus, Ohio, Tom Beaumont in Des Moines, Iowa, and Kasie Hunt in New York contributed to this report.