The woman, who has asked not to be named, met the 68-year-old bachelor on a dating site.
However, just three months after the wedding she made the stark discovery when flicking through one of his family albums at their home in Golden Beach, Miami.
She noticed a photograph of her own father — and the penny dropped.
Her new husband and dad had become estranged after the breakdown of his former marriage.
Despite this — the pair have said their bond is too strong to end the marriage now.
The granddad told the Florida Sun Post:
“They had a website with profiles of many attractive younger girls. I just felt something strange when I saw her photos.
“It was like a sense of deja vu, but at the time I couldn’t figure out why she seemed so familiar.
“We just hit it off right from when she walked into the restaurant.”
The bride said:
“When I saw my father in that photo album, I just felt an overwhelming sense of despair.”
The pair had apparently not discussed family too much before the big day.
She said:
“I feel our bond is so strong that even something like this is not enough to make us give up.”