Update: Marianne Gingrich told the Washington Post Thursday that in 1999 Newt Gingrich asked her to have an open marriage. Read the story here.

This revelation isn’t completely new. In the post below, I mention that Marianne told Esquire in 2010 that Gingrich had asked her to“tolerate” his affair with Callista Bisek.

Marianne Gingrich, wife of former House Speaker Newt Gingrich, looks up as she sits next to her attorney, John Mayoue, during a divorce hearing in Marietta, Ga., Nov. 11, 1999. (JOHN BAZEMORE/ASSOCIATED PRESS)

ABC reportedly has interviewed his second wife at length, and plans to air the interview on Thursday’s “Nightline,” just ahead of Saturday’s crucial South Carolina primary.

The Gingrich campaign must be nervous, because it issued a preemptive statement from the candidate’s two daughters from his first marriage, Kathy Lubbers and Jackie Gingrich Cushman: “Anyone who has had that experience,’’ the statement said, referring to divorce, “understands it is a personal tragedy filled with regrets, and sometimes differing memories of events.’’ A Gingrich aide prophylactically pinned the b-word on her, saying she was still “probably very bitter.”

What is it Gingrich is afraid his wife of 18 years is going to remember incorrectly? And what could be so bad that it would eclipse all that many Christian conservatives have already forgiven and forgotten about his history?

Just as interesting to me is ABC’s reported internal back-and-forth about whether to air the interview right before the primary. Does that mean they have legitimate questions about her credibility? Or that an ex-wife is by definition an iffy source? Or maybe they just fear the heat they’d take for giving voters even rock-solid negative information so soon before an election. (If the last is the case, I hope they do air it, because I never understood the worry that we can’t give voters information they might actually take into account.)

Or, say you’re in Marianne Gingrich’s shoes, and in possession of truly disqualifying information. Remember, you’re a red-hot Republican and also spent a lot of years in the service of your country, or that’s what you thought, anyway.

Do you protect yourself now by staying as far away from the action as possible? Or wait until the last possible minute to see which way the thing is going, and then spit it out if it comes to that?

It would depend on what it was, of course, but it would have to be pretty clear-cut, because no matter how pure your motives, you know it’s going to look like payback.

In an Esquire interview in 2010, Marianne Gingrich already painted an unflattering and highly detailed portrait of her ex. Here are just a few of the lowlights from that outing, in which Marianne Gingrich was described as chain-smoking Benson & Hedges while spilling that:

1. Newt actually started seeing his geometry teacher, the first Mrs. Newt Gingrich, when he was only 16. (I’d start the TV movie with that, but a career-ender, no).

2. Early in their marriage, she had to take over the budget “because it was too stressful for Newt.’’ Lots out there on “temperament” already.

3. That unlike Chris Christie, who recently told Oprah he’s over the stupid fat jokes, Newt found such remarks painful. “You know what he hated most?” Marianne says. “When they talked about him being fat. That weight thing was personal.” Endearing!

4. That after his Congressional career ended in scandal, he pretty much fell apart: “There were times,” Marianne told Esquire, “when he wasn’t functioning. He started yelling at people, which he’d never done before, and he’d get weirdly ‘overfocused’ on getting things done — manic, as if he was running out of time. He took to taking meetings while eating, slurping his food, as if he wasn’t aware or didn’t care how strange it looked.” If he ever sought treatment for depression, I would hope that wouldn’t be a disqualifier, but I wouldn’t bet on it.

5. That he has lost his way and wants more than anything a lifestyle that’s “opulent” or “self-indulgent.” Class warfare, anyone?

6. That he begged her to “tolerate” his affair with Callista, his third and current wife. Forgiven already.

7. That his conversion to Catholicism “has no meaning.’’ She can’t know that.

8. That he might go ahead and run for president anyway, because “he doesn’t connect things like normal people.’’ Does anyone who runs for president do that?

Whatever this new revelation is, it’s got to be worse than all of these. And for Marianne Gingrich’s sake, I hope she’s got proof.