In contrast to the impassive confessions to doping Armstrong gave in the first part of his interview with US talk show host Oprah Winfrey, Armstrong struggled with his emotions as he discussed the impact his fall had had on his family.
Eyes welling up and pausing to gather his composure, Armstrong recalled the moment he told his children the accusations against him were true and said the fallout from the affair had left his mother "a wreck".
The most humbling moment had come when he had to stand aside from Livestrong, the cancer foundation he established, he said.
"The ultimate crime is the betrayal of these people who support me and believed in me and they got lied to," he said.
Critics said Armstrong had shown little sign of contrition on Thursday, but in the second part of the interview aired on Friday there appeared to be genuine remorse.
The Texan conceded he deserved to be punished for years of doping that helped him win a record seven Tour de France titles.
However, he said the penalty he was given by the US Anti-Doping Agency was much harsher than the sanctions dished out to other self-confessed cheats, who were given lesser sentences for testifying against him.
"I am not saying that's unfair, I'm saying it is different," he said in a comment sure to infuriate his critics.
"I deserve to be punished but I am not sure I deserve the death penalty."
The 41-year-old said he had no ambitions to return to professional cycling but just wanted to be able to compete in sanctioned events, though he conceded his chances were slim.
"With this penalty, this punishment, I made my bed," he said. "Would I love to run the Chicago marathon when I am 50? I would love to do that but I can't.
"Realistically, I don't think that will happen and I've got to live with that."
Armstrong, who had always denied using banned substances until finally confessing in the interview with Winfrey, again refuted some of the accusations against him in a 1,000-page USADA report that led to his lifetime ban and the voiding of all his race wins.
He denied claims he continued using drugs when he made his comeback in 2009 and said there was no truth to suggestions a representative of his tried to pay off USADA to drop their investigation into him.
"That is not true," he snapped. "I think they (USADA) said it was $250,000, it was broad number and that's a lot of money. I would know about that."
With his reputation already seemingly beyond repair, the second part of the interview focused on his personal torment rather than his sins.
He admitted he was ashamed of what he had done and was closest to tears recalling the moment he told his children that the accusations against him were true.
"I saw my son (Luke) defending me and saying, 'That's not true' ... that's when I knew I had to tell him. He never asked me, 'Dad is this true?' He trusts me," Armstrong said.
"I said, 'Listen, there's been a lot questions about your dad, did I dope and did not dope? ... I want you to know that it is true'.
"I told Luke, 'Don't defend me anymore ... if anyone says anything to you do not defend, just say, hey my dad said he was sorry.'" Armstrong said the scandal had taken a toll on his mother, saying "she's a wreck", and had hit him financially.
He said he lost about $75 million when his sponsors deserted him last year after USADA released its damning report on him.
"All gone. Probably never coming back," he said. "I've lost all future income."
The cancer survivor is already facing a string of challenges that could cost him millions more but said the lowest point was when he had to quit the Livestrong foundation.
"That was most humbling moment," said Armstrong, who survived testicular cancer before going on to win the Tour de France seven times.
Armstrong said he had no idea what the future held but said he hoped he could rebuild his life.
"I've been to a dark place that was not of my doing where I didn't know if I would live," he said.
"You can't compare this to an advanced diagnosis. That sets the bar. It is close but I'm an optimist and I like to look forward."
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