"I don't want him to be president, and I don't think he should be," Marianne Gingrich said in a Vanity Fair article. "It's not so much what he'd be doing. It's what I'd be doing," she said, adding that she did not see her husband very much.
"He can't do it without me. I told him if I'm not in agreement ... it's easy. I just go on the air the next day and I undermine everything."
The article said Mr Gingrich, who promotes family values, had several affairs during his first marriage, may be having problems in his second marriage, and is unable to keep friends or employees.
The Republican leader has not ruled out the possibility of running for president next year, but has so far not made his intentions clear.
Tony Blankley, Mr Gingrich's chief spokesman in Washington, described the article as "tabloid psycho-babble," adding: "It's too low on the food chain to justify serious comment."
The article, written by the best-selling author Gail Sheehy, who wrote Passages, quotes a woman who describes herself as a former mistress of Mr Gingrich in the late 1970s calling him "morally dishonest." The woman, Anne Hollander, was quoted as saying she had an affair with Mr Gingrich during his first marriage. "We had oral sex. He prefers that modus operandi because then he can say, 'I never slept with her'," she said.
Ms Hollander said that Mr Gingrich once threatened her by saying: "If you ever tell anyone about this [their affair], I'll say you're lying." The article quotes Gingrich associates as describing him as a man with maniacal drive, an obsession with artificial deadlines, the possessor of a frenetic psyche and a warrior personality.