Newt Gingrich denied claims by his second ex-wife Thursday that he once asked her to agree to an “open marriage,” kicking off a presidential debate in South Carolina with a fiery defense of his personal life.

“The story is false,” Gingrich said.

The former House speaker was asked about a pair of interviews his ex-wife Marianne granted in which she leveled the charge about him seeking an open marriage – at the time, Gingrich was seeing Callista, whom he later married.

Gingrich confronted CNN moderator John King, who posed the question about Marianne’s claims at the very top of the debate.

“I am appalled that you would begin a presidential debate on a topic like that,” Gingrich said. “To take an ex-wife and make it, two days before the primary, a significant question in a presidential campaign, is as close to despicable as anything I can imagine.”

He added, “I am frankly astounded that CNN would take trash like that and use it to open a presidential debate.”