Tori, 43, and Dean wed in 2006, but their marriage was rocked seven years later when the latter was accused of cheating on her with Emily Goodhand.
In 2014, he entered rehab to treat "health and personal issues". The events were covered in docu-series True Tori.
After working on their marriage, Dean pledged his love to the former "Beverly Hills, 90210" star once again by proposing to her in Paris in April surrounded by their kids.
The couple is now expecting its fifth child next year and couldn't be happier, reported People magazine.
"Everything crashed (three years ago). We had to start over. We had to completely rebuild... We made the conscious decision based on our love for each other to tough it out and work through it.
"It was one of the worst times in our lives, but it was also one of the best times. I wouldn't change anything because if we hadn't started talking and opened up those lines of communication, maybe we wouldn't be here today.