The 37-year-old actor confessed in an interview with The Breakfast Show with Nick Grimshaw on BBC Radio 1 that Dewan "broke down crying" after he tried to mislead her before popping the question.
"When I proposed to my wife I did something pretty cruel because I thought she was onto me," Tatum told host Nick Grimshaw. "I basically told her I never wanted to get married to try to throw her off."
"I told her, 'I don't believe in the institution of marriage and I don't think I ever want to get married,'" he recounted. "She basically broke down crying. I thought, 'This is not going well at all,' so I had to propose to her sooner than later."
People reported Tatum ultimately proposed to Dewan in front of their close friends during a trip to Maui, Hawaii. The couple, who met on the set of the movie Step Up, married in July 2009, and welcomed daughter Everly in May 2013.
"We were like, 'What do you mean? This is a real movie!'" he recalled. "And, like, 10 more seconds went by and she was like, 'Please, can I watch a real movie?' And were like, 'Fine, just put on Moana.'"
Tatum will next star in Kingsman: The Golden Circle with Taron Egerton.