CHICAGO — Lance Armstrong finally cracked. Not while expressing deep remorse or regrets, though there was plenty of that in Friday night's second part of Armstrong's interview with Oprah Winfrey. It wasn't over the $75 million in sponsorship deals that evaporated over the course of two days, or having to walk away from the Livestrong cancer charity he founded and called his "sixth child." It wasn't even about his lifetime ban from competition, though he said that was more than he deserved. It was another bit of collateral damage that Armstrong said he wasn't prepared to deal with. "I saw my son defending me and saying, `That's not true. What you're saying about my dad is not true,'" Armstrong recalled. "That's when I knew I had to tell him." Armstrong was near tears at that point, referring to 13-year-old Luke, the oldest of his five children. He blinked, looked away from Winfrey, and with his lip trembling, struggled to compose himself. It came just past the midpoint of the hourlong program on Winfrey's OWN network. In the first part, broadcast Thursday, the disgraced cycling champion admitted using performance-enhancing drugs when he won seven straight Tour de France titles. Critics said he hadn't been contrite enough in the first half of the interview, which was taped Monday in Austin, but Armstrong seemed to lose his composure when Winfrey zeroed in on the emotional drama involving his personal life. Lance Armstrong's Confession - Oprah's Next Chapter - Oprah Winfrey Network