Sarra Hoy, 34, said she has never "got over London" because of the stress of supporting Sir Chris as he strived to make the historic home Olympics.
The lawyer, who married the champion cyclist in Edinburgh's St Giles' Cathedral in April 2010, said he told her after one session he feared his heart would burst.
She said that for months, she would drive to and from work in floods of tears, then compose herself before seeing her husband so he never knew her pain.
She revealed she had not told the six-time Olympic gold medal winner, Britain's greatest Olympian.
Speaking on a BBC Scotland documentary, Sir Chris Hoy: How To Win Gold, she said: "I'd see him come home, having put so much effort into the training sessions that would leave him just absolutely physically exhausted and fatigued and in pain.
"He told me he'd been doing some training session and he'd worked so hard and pushed himself to such a limit he thought his heart was going to burst. That's difficult for a wife to hear.
"Three months before the Games, I would drive to work in tears and I would drive home from work in tears, and then I would compose myself and go inside the house.
"That was purely, I think, looking back, how I let off steam and coped with the stress of it so that I would never let that on to Chris that I was feeling it as well. I've never told him that."
Sarra, from Edinburgh said she helped by making sure Sir Chris did not have to expend any unnecessary energy. And she did everything around the home, to stop him using his legs.
"Cyclists are famous for not spending any time on their feet if they don't have to, and that's kind of how I tried to help him.
"I would do anything that I thought might save his legs, even for that one second.
"If it's all about marginal gains, then I began to think 'ok, I'm going to help him at home with that'.
"He didn't have to think about food preparation, cooking, cleaning, bills, paperwork, or anything in the house. Basically, he could just come home and nurse his aches and pains, but wouldn't be using any extra energy by doing all of these other things that I could help him with."
The couple met in the fashionable Grand Cru bar in the centre of Edinburgh at a mutual friend's birthday party in 2006, and married in 2010.
Sir Chris, 37, who retired after the London Games, revealed last month they are expecting their first child,
Speaking in the hour-long documentary, he pays tribute to his wife, adding: "Thanks to Sarra and the rest of the support around me, I hit my targets for two of the three events, and made the team for London, the home Games, and for me, at 36, my final Olympics.
"In the first event, the team sprint, we won gold. It was my fifth, equal to Sir Steve Redgrave."
l Sir Chris Hoy: How To Win Gold, will be shown on BBC One Scotland, Wednesday, July 16, at 9pm.