ABC News is out with this preview and some excerpts from its hotly anticipated interview with Newt Gingrich's (second) ex-wife, Marianne, that's set to air tonight. It's catastrophic.

While this isn't the first time we've heard her harshest accusations, it is the first time we've heard them on national television two days before her ex's great chance in the South Carolina presidential primary that will make or break his campaign.

Marianne Gingrich tells ABC that Newt asked her to "share him" with his then-mistress, the current Callista Gingrich, after confessing to their six-year affair. "He wanted an open marriage and I refused," she says, and then explains how Newt and Callista would carry on their affair "in my bedroom in our apartment in Washington."

"He always called me at night," she recalled, "and always ended with 'I love you.' Well, she was listening."

What could be worse? This gives it a run for its money:

She said Newt moved for the divorce just months after she had been diagnosed with Multiple Sclerosis, with her then-husband present.

"He also was advised by the doctor when I was sitting there that I was not to be under stress. He knew," she said.

She says she's speaking out because she feels Newt lacks the "moral character" to be president. We'd suggest that "getting sweet, sweet holy revenge" hits closer to the mark, but either works.