"Everything that I did was at the direction of John Edwards, everything," Young said. "So I don't understand how the senator could even begin to deny that he was involved in every aspect of this."
Edwards issued a statement in May 2009 saying he was "confident that no funds from my campaign were used improperly."
Young said he provided phone records, hotel bills, videos and voice mails, documenting the time he spent hiding Edwards' mistress with virtually unlimited funds to the grand jury and was given "limited immunity."
Young told Woodruff any benefit he got from the cover-up is balanced by the reality that he has been unemployable for 2½ years. Young said he had to write "The Politician" to survive financially. Their sole source of financial support is his wife's work as a nurse.
But in his book, Young writes that about midway through their several months on the lam in five-star hideaways, they set aside thousands of dollars of Mellon's money for "future use."
Asked by Woodruff if the money was still set aside, Young said it had all been spent.
"The money went into the house and we were supposed to sell the house and go somewhere else," Young said. "We couldn't come back to Chapel Hill."
The Young's 5,300 square foot home -- just three miles from the Edwards' mansion and valued by the tax assessor at $893,000 -- was built, in part, with a $325,000 gift from Baron, who wired the money directly to the builder, according to Young. The Youngs claim they were encouraged by Baron to build the house with no expense spared, and then sell it and move to another city.
"We've completely lost our reputation. We have a house that we can't finish that's threatening to bankrupt us," he said. "We were seduced by the power and the lights and the money ... we were. And there's no excuse for that. There's no excuse for a lot of our behavior."
"It's not something we're proud of. It's not something, we're humiliated, we're embarrassed ... we know we made the wrong decision," Cheri Young said.
August 2008, shortly after Edwards admitted to ABC News that he'd cheated on his wife in an exclusive interview with Woodruff, was the last time Young saw Edwards. But the decisions Young made still haunt him.
"For myself, I am so sorry for my part in this. I am so sorry for what I did to my family," he told ABC News. "This is going to be on my tombstone."
Watch "20/20" at 10 p.m. ET and "Nightline" at 11:35 p.m. ET Friday, Jan. 29, to see Andrew Young's exclusive interview. Then tune in to "Good Morning America" Monday, Feb. 1, when Young will appear for his first live interview.