“I wasn’t looking for it,” Dewan, 38, tells PEOPLE in this week’s issue. “But it sort of took me by complete storm. It happened when I least expected it.”
The actress and Tony winner, 43, originally met years ago, but only briefly.
“I had met Steve years ago in a flash, it must’ve been five minutes,” she recalls. “I saw him perform in Once on Broadway and I was just totally blown away by his talent. My mom was with me, and we got to go backstage and meet the actors. He just had a cool [energy] about him.”
She adds: “Obviously I was married and so we never spoke or saw each other again for six years, but I never forgot the moment. And then six years later, obviously it becomes public knowledge that we’re separated and he contacted me.”
Timing was everything, Dewan says, as she was just coming “out of my grief tunnel,” months after announcing the end of her nearly nine-year marriage to Channing Tatum.
Watch the full episode of People Features: Jenna Dewan, streaming now on PeopleTV.com, or download the PeopleTV app on your favorite device
“I had kind of come to terms with, ‘Okay, I need to accept that I need to start a new life.’ I had no idea what I was looking for, and I was not at all looking for any kind of relationship,” she says. “It was nothing I was looking for, but it was everything I needed, if that makes sense.”
For much more about Jenna Dewan and her new book, Gracefully You, pick up the latest issue of PEOPLE, on newsstands Friday
They started with a phone call, which lasted for hours and Dewan says there was an “immediate connection,” even more so when they met in person.
“It was an instant connection when we met each other. All of a sudden,” she says with a smile. “There was no way we could avoid it. So in my eyes it was truly, completely meant to be. There was like a lightning bolt behind it.”
Dewan says she was cautious in the beginning, but trusted her instincts.
“I definitely was like, ‘Okay, let me move through this slowly.’ But it was too strong. It was too right,” she says. “And I said, ‘What am I fighting?'”
One aspect of their relationship that took some time for Dewan was deciding when it was right to introduce him to her daughter Everly, 6, whom she shares with Tatum.
“That was the thing I waited for a very, very, very long time,” she says. “I wanted to make sure, I’m very protective of her and she had gone through a lot of great change, so I wanted it to be at a time that I felt like she will be ready for. And I knew immediately he was going to be wonderful with her.”
Kazee and Everly got along almost instantly, says Dewan, but he earned Everly’s full stamp of approval when he sent her a video of him playing guitar and singing a My Little Pony song.
“[Everly’s] little face was like, ‘He can sing My Little Pony on the guitar?’ And I was like, ‘How amazing is this man?'” Dewan says with a laugh.
And now, Dewan and Kazee are happily entering another new life chapter together — they are expecting a baby, Kazee’s first.
“I always said that I would love to expand my family. I was so excited by the option to do that,” she says. “The second I knew, I was thrilled with it.”
Dewan’s book, Gracefully You: How to Live Your Best Life Every Day, hits bookshelves on Oct. 22.