WASHINGTON (AP) - Newt Gingrich's second wife says the GOP presidential candidate asked her for an "open marriage" in which
he could have both a wife and a mistress.

In an interview with ABC News' "Nightline" scheduled to air Thursday night, Marianne Gingrich says she refused to go along with
the proposal.

The interview is airing just two days before the South Carolina presidential primary, and as Gingrich is gaining ground on GOP
front-runner Mitt Romney.

Marianne Gingrich was the candidate's second wife. He is now married to Callista Gingrich, with whom he has acknowledged having an affair.

In excerpts of the interview released by ABC, Marianne Gingrich said Gingrich conducted his affair with Callista "in my bedroom in
our apartment in Washington."

If you missed the video that aired on Nightline, it is available below.

(Copyright 2012 by The Associated Press. All Rights Reserved.)