SIDEBAR: Candidate's ex-wife: Gingrich unfit to be president

Jan 19, 2012, 20:19 GMT

Washington - Republican candidate Newt Gingrich's extramarital affairs make him morally unfit to be president, an ex-wife said in an explosive interview to be broadcast Thursday.

In an interview with ABC News, Marianne Gingrich detailed the end of the pair's 18-year marriage and her husband's request that they have an 'open marriage' so he could continue an affair with the woman who is now his third wife.

'He wanted an open marriage and I refused,' she said in excerpts of the interview released before it aired.

The allegations could hurt Gingrich's presidential bid before the South Carolina primary Saturday even as he picked up an endorsement Thursday from Texas Governor Rick Perry as he quit the race.

Gingrich's marital indiscretions are not new, and he has raised them in past debates saying he sought forgiveness from God. Perry, in endorsing Gingrich, indicated that he did not feel the candidate's past behaviour disqualified him from being president.

However, the juicy details of the end of the marriage might be a burden ahead of South Carolina, where socially conservative evangelical Christians are politically important.

Gingrich is now in a virtual tie with frontrunner Mitt Romney in South Carolina. Three polls released Thursday show him 2-3 percentage points ahead of Romney, who has led by large margins in past opinion surveys.

Newt and Marianne Gingrich divorced after the affair became known and he later married his mistress, Callista, who now appears by his side at most campaign events. Gingrich also divorced his first wife, Jackie, while she was receiving cancer treatment.