She probably needs a hearing aid;)
What he said: “I want this marriage to be OVER (not open)!!!!
They just played a clip from the interview on the radio. Marianne said, "He said, 'You want me all to yourself; Calista doesn't care what I do.'" The interviewer asked, "And what do you think he meant?" Marianne: "He wanted an open marriage."
If the quote from Newt is accurate, it sounds more to me like Marianne -- who, according to Rush today, didn't like the public aspects of Newt's life (though she seems to have got over an aversion to publicity!) -- wanted to run every minute of his day (she called him 10 times a day???) and be central over his career. Seems likely that her demands were a constant and perhaps growing source of stress in the marriage before he ever met Calista.
The "open marriage" bit seems to be her own interpretation rather than a quote.