The star, who is now dating businessman Steve Kazee - and expecting his child, admits divorce hit her really hard and forced her to take another look at her life after she and Channing drifted apart.
"I always say no one gets married to hopefully get divorced," she told People magazine. "People grow and they change and sometimes they don't grow and change together. So it wasn't an overnight thing that happened. There was no one event. I think it was just a slow realisation that we wanted different things."
"I was just gutted. It was so difficult for me. It was the loss of an idealistic future for myself and my life... I met him (Tatum) when I was 24, I didn't know life without Chan... It was a hard journey of growth and change."
Jenna now insists she's in a "joyful new place" in her life as she prepares to become a mum again, adding, "You would never expect your life to take a turn the way it does, but embracing it and starting fresh and figuring out what you want in life and what means a lot to you and what's meaningful, what is going to make you happy."
"I'm grateful that I now am at a place where I understand myself and what I want and I’m happy about this new chapter."
Jenna is sharing a few life lessons in her new book, "Gracefully You: How to Live Your Best Life Every Day", which will be released later this month, and she has signed on to host quirky new U.S. dating show "Flirty Dancing" this Christmas.