Gingrich denies ex-wife's "open marriage" claim Newt Gingrich responded angrily to questions about his personal life on Thursday night, saying he was "appalled" to be asked about allegations from one of his ex-wives as the Republican presidential nomination contest moved to South Carolina. Less than 36 hours before South Carolina becomes the third state to vote for the Republican nominee, Marianne Gingrich, the former House speaker's second wife, claimed that her husband divorced her after she would not agree to have an "open marriage." The allegations, made in an interview with ABC News, formed the basis of the opening question in a much-anticipated debate on CNN on Thursday night, the last time the four remaining candidates will appear together before Saturday's primary election in South Carolina. "I'm appalled that you would begin a presidential debate on a topic like that," Mr Gingrich told John King, the debate moderator, when asked about the allegations, the opening salvo in a tirade against the mainstream media. "I'm tired of the elite media protecting Barack Obama," Mr Gingrich said, saying his ex-wife's claims were "false." Marianne Gingrich claimed that the former speaker had already started having an affair with his former congressional aide and current wife, Callista, when he made the request. His chief rival for the nomination, national front-runner Mitt Romney, declined to get drawn into the matter. "Let's get on to the real issues," Mr Romney said when asked to comment. The debate focused on immigration, healthcare and taxes, making it notable for the pressing issues that were barely discussed: jobs and the economy, and foreign threats such as the European debt crisis and an increasingly hostile Iran. During the debate, Mr Gingrich's campaign released his tax return, showing he and his wife Callista paid $994,708 in federal taxes last year on an adjusted gross income of $3.14m. Their tax rate of 31.5 per cent is twice that which Mr Romney said he paid. Earlier this week, under pressure to release his tax records, the front-runner disclosed he paid "close to" 15 per cent because most of his income was from investments. Mr Romney said during the CNN debate that he would "probably" release his returns from 2011 as well as previous years "when my taxes are complete for this year and I know if I'm the nominee." Mr Gingrich has pressed him to release the returns immediately so that the Republican party knows before, not after, it has chosen its nominee whether there would be any campaign-sinking details in the documents. Mr Romney said he was waiting for his latest returns to be completed so he could release them at the same time and stop the issue being dragged out in the media, to boos from the crowd. "I want to make sure that I beat President Obama, and every time we release things drip by drip the Democrats go out with another array of attacks as have been done in the past," he said. If I'm the nominee, I'll put these out at one time so we have one discussion of all this. The tax question continues to hang over Mr Romney, while Mr Gingrich's campaign could suffer from his ex-wife's claims. South Carolina is the first southern state to vote and Mr Gingrich, who hails from neighbouring Georgia, has been surging in the polls in recent days, honing in on front-runner Mitt Romney. A win for Mr Gingrich in South Carolina would remove the air of inevitability from Mr Romney's campaign and would cap a terrible week for the multi-millionaire former private equity chief. "I just stared at him and he said, "Callista doesn't care what I do."" Mr Gingrich has never denied his wrong-doings but has repeatedly said they were wrong and that he had repented. Some South Carolina evangelicals, already sceptical about the candidate given his conversion from Southern Baptist to Catholicism, Callista Gingrich's denomination, say they can not support him but others accept that he has asked forgiveness from God. Mr Gingrich was speaker and leading impeachment proceedings against President Bill Clinton over his affair with former White House intern Monica Lewinsky, while at the same time having an affair with Callista. He added that Mr Gingrich had acted better than Mr Clinton, who he claimed also wanted an open marriage.