Bell teared up when addressing Shepard's struggles with addiction. "He knows the value of things. He was an addict for many, many years and he pulled himself out of it, and he's been sober for 11, 12 years now," she said. "And he knows how many times he's messed up and how many times he's been really close to losing everything."
The Bad Moms actress married Shepard, 41, in 2013 and -- unlike many celebrity weddings -- it was a simple and private affair.
"We got married in a tiny room in the Beverly Hills courthouse, and it was still one of the best days of my life," she said.
In their wedding photos, which Bell shared for the first time during the interview, she wore a simple black outfit with decorative collar, while Shepard sported a tux.
ET caught up with Bell and Ted Danson, her co-star on the upcoming NBC sitcom The Good Place, at Comic-Con last week, where we asked them to describe their personal "good place." For Bell, it was a humid summer night in Michigan with Shepherd and their two daughters, 3-year-old Lincoln and 19-month-old Delta.