Following the cyclist's televised admission to Oprah Winfrey, Crow, 50, appeared on Entertainment Tonight, where she briefly discussed the scandal surrounding her ex.
"I know how hard he worked to win those titles, and you know, it was hard to watch," Crow said, referring to his Tour de France wins. (In August, Armstrong, 41, was stripped of his seven Tour de France titles.)
Crow says she caught bits and pieces of Armstrong's two-part interview with Winfrey. "I felt bad. I felt bad for him, I felt bad for his family and I kind of felt like the rest of America," said the singer. "He is a hero we watched and looked up to and admire."
But Crow believes at least Armstrong now feels a sense of relief.
"I think that honesty is always the best bet and that the truth will always set you free," she said. "It's got to be really hard walking around, knowing you're not telling the truth about something. I always contend that the truth is the best way to go."
Banned for life from competing, the athlete originally vehemently denied the doping claims.
Crow, who dated Armstrong from 2003 to 2006, did not discuss speculation about whether or not she knew the cyclist was involved in doping.