Test Text1 italics Test Text1 plain Reporter: Here it is, the epicenter of power on our planet. Well, it's the set of scandal but that's as close as I'm going to come. It's time for number one and man... See More
Test Text1 italics Test Text1 plain Reporter: Here it is, the epicenter of power on our planet. Well, it's the set of scandal but that's as close as I'm going to come. It's time for number one and man with a burning desire to sit right here. It's time for our scandal of the century. Flying high at number one -- john edwards. Amazing just how far he went, knowing that one of the most sensational scandals in american history was mildewing behind his million dollar smile. It was 2007. Many thought hilary clinton was damaged goods and a guy called barack obama just too wet behind the ears. John edwards was lookin' like the next president of the united states. He was easily the best possible candidate we had. Reporter: And his greatest political asset, his wife elizabeth. My rock, my love, john edwards. Reporter: She was a breast cancer survivor. I remember thinking that is the most natural marital partnership I've ever seen in politics. This is, so -- I was -- I -- it shows you how good a judge I am of that kind of stuff. Reporter: Edwards was travelling the country drumming up support for a presidential run when he met a feisty wannabe actress and movie producer named rielle hunter. So he rounded the street corner and it came out of my mouth, "you're so hot." Reporter: Street corner? Didn't they meet in a bar? Anyway. You're on the campaign trail. How do you actually have the time to saddle up next to somebody, and go, "hey, my name's john, what's yours?" Reporter: They, um, pardon my french, had sex that first night. Chances are high this was -- I'd be left with memories. That was it. Reporter: But that was oh so far from it. I couldn't believe he was calling me. We could not get enough of each other. Reporter: And edwards hired hunter to make a behind the scenes film of the campaign. Perfect cover. I wanna be with the guy i love. And I thought that making the documentaries would help show the side that he is with me. Can you read it? Yes, I can read it. Reporter: How sweet. But then one day, nine months later, their illicit bliss was shattered. Elizabeth edwards heard a cell phone ring, the secret cell phone her husband used only for rielle. Elizabeth called back the number. And I said, "hey, baby." Click. Mrs. Edwards was a screamer. But it was just a one night stand, that's what he told her. Reporter: But the affair continued, even when elizabeth's cancer returned. This time, inoperable. We're gonna always look for the silver lining; it's who we are as people. Reporter: Behind that public front elizabeth suspected her husband was still having an affair. Edwards made much of his wife. My wife is the finest human being I've ever known. Every time he would go on tv he would talk about how much he loved his wife, rielle would go crazy. Reporter: Caught between a dying wife and a demanding mistress and running for president, he was in no need of additional drama. In may of 2007, he got it anyway. Rielle was pregnant. He was cussing her out calling her crazy and saying that she had sworn to him that she was physically unable to get pregnant and he felt like he had been set up. He tried to convince me to convince rielle to have an abortion. Then the phone rang from the "national enquirer." A friend of miss hunter has been telling her friends that she had met a man who was married and she had fallen in love with him. It's completely untrue, it's ridiculous. I've been in love with the same woman for 30 plus years. Reporter: Really? John edwards continued campaigning and sleeping with rielle hunter. Then the enchoirer published a follow up. Is the baby yours? Not true. Reporter: Edwards had a cunning plan and turned to his staffer, andrew young. He wanted me to issue a statement claiming paternity. Reporter: Slight complication, andrew young is married. Here's his wife. I really about fell over. How could john edwards ask you to do that. Reporter: And baby mama? Insane. That was my reaction. That is the stupidest idea I've ever heard. Nobody will buy that. Reporter: They all went along with edwards plan and people did buy it largely because no one wanted to believe edwards could possibly be cheating on his wife. Meanwhile young said he was receiving money from wealthy donors to keep hunter and her bump out of the public eye. Money was no object. We were living in mansions flying around in jets. Reporter: When rielle gave birth to a baby girl, his goose was kicked. He was spotted visiting his girls, mama and baby. We said are you here to see your love child? He looked like his world had just passed him by, like I'm done. He called me the neck morning. He was bawling. He said I've been caught. I've been caught. How could you have done this? First of all, it happened during a period after she was in remission from cancer. Reporter: Edwards blamed his early successes -- all of which was a self-focus, an egoism, narcissism that believes you to think that you can do whatever you want. Is this affair completely over? Oh, yes, for a long time. What were you thinking? This is personal to my family. My family knew all about it. That's a lie. The baby is miss hunter is your baby, true? Not true. That's a lie. I know it's not possible that this child could be fine. I would welcome a paternity test. Two lies. People worked for you, voted for you. What do you think they think about you now? One of the purposes of this interview is to tell the truth. And that's a lie about the other lies which is true. Reporter: Elizabeth edwards finally learned the truth and began divorce proceedings but she died before the papers came through. This scandal exposed a level of recklessness, deviousness, callousness, narcissism that if you look at it long enough is a little terrifying. Reporter: Just two weeks ago rielle hunter publicly apologized. I behaved badly she wrote in the handcuffington post, promoting her new bo. Her off spring is now five years old old but they're no longer together. John edwards' political career is toast. He's hit the speaking circuit. I don't think god is through with me. I believe he thinks there are still some good things that i can do. I don't think that god is done with me yet. I don't want to speak for god but I'm pretty sure he's passed you off to his colleague down south. closed?
This transcript has been automatically generated and may not be 100% accurate.