The singer made the revelation during a recent interview with The Guardian.
Legend and Teigen met in 2007, when the model was cast as the love interest in the music video for his song "Stereo."
"We spent the whole day dancing together, grinding together," he said. "And, uh, we made a music video."
They became a couple and have been together for more than a decade other than, Legend told the publication, an attempted breakup that lasted only half an hour.
"I was really stressed and busy," he said. "I was just like: 'I'd just be happier single right now,' and she was like: 'No.'"
On Monday, Teigen tweeted "11 years later baby."
"It wasn't a typical breakup," Teigen added in her tweet. "He was on tour and his voice hurt and he was being a whiny face about everything and so yeah, I was like 'no.'"
The couple married in 2013 and are parents of a young daughter. Legend credits his wife with helping him become a better person.
"She pushes me to be funnier," he said. "Not because she's trying to, I think it's just being around her. And to be bolder."