"Mrs Romney, who will travel to London next week with her husband to attend the opening ceremony of the Olympic Games, said that horses had become her passion and joy in life after she was diagnosed with MS nearly 14 years ago.
"Horses have been my therapy, they've been my joy, my passion in life, I wish everyone could have a passion, like I have this passion," she said, "I love horses; they have been my companion through my dark hours as I was recovering, they gave me strength and joy and hope.
Now in remission, Mrs Romney spoke frankly about her battle against the disease and how it had taught her to understand the meaning of suffering and the value of her family – husband, five sons and now 18 grandchildren.
"It humbled me. It crushed me to dust. And they when it leaves you there with nothing, then you have to learn to say 'what are the little pieces I can start to pick up, that can give value to my life again?'," she recalled.
"Of course that is family and friends. Those are the people that saved me and rallied around me in my darkest hour, because I went in a pretty dark hole." Mrs Romney, who has Welsh ancestry, has become an important part of her husband's campaign, softening his image as a management titan who has an awkward manner with ordinary voters.
She added that her experience with MS had enabled her to sympathise and understand people who were facing difficulties.
"I can relate to someone whose going through a really hard time, because I can say 'I know what you feel like, I know how hard it is," she said on Good Morning America."