The dancer, actress and TV personalty, has opened up about the painful split in her new book "Gracefully You: How to Live Your Best Life Every Day", revealing she was determined to remove the pain she felt in the marriage and protect the pair's six-year-old daughter, Everly.
"I'd come to realise the dynamic I was in wasn't serving me, nor was it serving my daughter," Dewan writes. "First and foremost I had to accept the realisation this isn't working and had moved into hurting."
The pair decided to divorce just before she began filming the second season of her reality series "World of Dance", and she and Tatum agreed to keep the news a secret during the shoot.
"The public saw Channing and I in this idealised romanticised light," she adds. "This made things difficult for me because I like being as honest and real as I can."
Dewan and Tatum met on the set of the 2006 dance romance "Step Up" and married in 2009. They split in April 2018.
The 38-year-old has since found romance again with actor and singer Steve Kazee, the father of her unborn second child.
"I wasn't looking for it," Dewan says of finding love with the Tony Award winner, "but it sort of took me by complete storm. It happened when I least expected it."
"Gracefully You: How to Live Your Best Life Every Day" is now available.