Marianne Gingrich Says Newt Wanted Open Marriage, Lacks Moral Character to Be President

Just 48 hours before the critical South Carolina primary, Republican presidential candidate Newt Gingrich's ex-wife Marianne is criticizing the former House Speaker's character.

Marianne Gingrich says, in an interview airing tonight on Nightline, that Newt's professed positions on marriage and family values do not line up with his actions.

Their 18-year marriage ended in 1999, and during that span, Marianne says Newt Gingrich admitted to her about a six-year affair with a Congressional aide.

That woman is now Newt's third wife, Callista Gingrich. This is well documented, but it's a comment Newt allegedly made about it that's raising eyebrows:

He asked his wife if she would share him with Callista, according to Marianne.

"I just stared at him and he said, 'Callista doesn't care what I do.' He wanted an open marriage and I refused," Marianne Gingrich tells ABC News.

Marianne also details how Newt was conducting this affair while publicly condemning the unfaithful President Clinton for his lack of moral leadership.

“How could he ask me for a divorce on Monday and within 48 hours give a speech on family values and talk about how people treat people?” she said.

“Truthfully, my whole purpose is to get out there about who I am, so Newt couldn’t create me as an evil, awful person, which was starting to happen.”

It gets worse. Newt divorced Marianne months after she was diagnosed with Multiple Sclerosis, she says, and began dating her almost as scandalously.

Her relationship with Newt started before his divorce from his first wife, Jackie, was finalized. And he left Jackie while she was undergoing cancer treatment.

Political pundits call this "baggage." Can he overcome it? Newt, who is trying to sustain recent momentum, responded to this interview on Today, saying:

"I'm not going to say anything negative about Marianne."

"My two daughters, Kathy and Jackie, have sent a letter to the president of ABC News saying from a family perspective, they think this is totally wrong."

"They think that ABC should not air anything like this. And that intruding into family things that are more than a decade old are simply wrong."

"I think that my two daughters are very credible on my character, I think the people who have known me a long time are credible on my character."

"We have lots of folks willing to speak on this, I'm not going to."

The letter of which he speaks that his daughters wrote says, "The failure of a marriage is a terrible and emotional experience for everyone involved."

Newt "regrets any pain he may have caused in the past to people he loves," they say, echoing sentiments Newt has made on the campaign trail.

Gingrich often speaks of his mistakes, admitting he is imperfect. The question is now much baggage is too much for voters to potentially take.

He should get a modest boost from Rick Perry dropping out of the race today, and has another debate tonight to make his case in South Carolina.