Sheen, 50, has had a troubled history with drug addiction, pornography and prostitutes.
Richards spoke about the former "Two and a Half Men" star during a chat with Allegedly With Theo Von and Matthew Cole Weiss last week, reported Us magazine.
When asked about her history of dating "bad boys", Richards, 44, said, "Charlie, when I married him, he wasn't a bad boy. He was sober for almost four years. He was a very different person. His lifestyle was very, very different. He was a former bad boy, I guess," the mom to their two daughters Sam, 11, and Lola, 10, said.
The former couple got divorced in 2006, Nowadays, however, Sheen and Richards have patched things up.
"[It's] up and down," she said of her current relationship with Sheen. "I'm always here [for him,] but he's an addict. For better or worse, he's going to be in my life for the rest of my life so I personally like to keep the peace.