Armstrong admitted to doping during yesterday's televised interview with Oprah Winfrey, saying he never worried about getting caught as there was no out-of-competition testing at that time.
McEwan says it is something he will not be able to get over.
"I don't think you can, when you have been deceived for that long," he said.
"Not only bike riders, but the fans, the press, everybody wanted to believe the beautiful story, the hero, and all that stuff and that all gets brought down."
But McEwen says it would not be so easy to do what Armstrong did now.
"Cycling changed seven years ago and he said that himself," he said.
"The big change that was made was the introduction of the biological passport, the whereabouts system, and that has made it, I would say, virtually impossible for the same thing to happen twice - touch wood, I mean, you never know," he said.
Two-time Tour de France stage winner Stuart O'Grady says it is time for cycling to move on and work to fix the damage Armstrong has done.
"It is cycling that has suffered through all this, so hopefully through Lance's confessions we can start looking to the future and hopefully something good can come out of this," he said.
Meanwhile, Armstrong's assertion that he did not take performance-enhancing drugs after his seventh and final Tour victory in 2005 has been dismissed by the president of the World Anti-Doping Agency (WADA).
In his interview with Winfrey, the American maintained he was clean when he made a comeback in 2009, 3.5 years after retiring.
However, WADA chief John Fahey told Britain's Daily Telegraph on Friday: "The evidence from USADA (United States Anti-Doping Agency) is that Armstrong's blood tests show variations in his blood that show with absolute certainty he was doping after 2005."
"Believe USADA or believe Armstrong? I know who to believe.
"It struck me that the statute of limitations under US law might be relevant and Armstrong would not want to admit to anything in regards to his comeback that might be picked up under the US criminal code."
"This bloke is a cheat and did my view of him change after watching the interview? No."
The harm that Armstrong caused his family, sponsors and fellow cancer survivors by years of lying and denials of doping will be revealed in part two of his interview with Winfrey to be aired today.
Clips showed Armstrong would talk about his future, how his family had to face the truth, his reaction when sponsors dropped him after evidence of his drug taking emerged and the most humbling moment of his epic fall from grace.
"I will spend the rest of my life trying to earn back trust and apologise to people," Armstrong said in the first part of the interview.
Armstrong has withdrawn from his roles with Livestrong, the cancer charity he founded.
The patients he inspired with his rise from testicular cancer survivor to Tour de France winner from 1999-2005, meanwhile, are dealing with the admission that the cyclist's fairy-tale story was built upon "one big lie".