Sheen told the CBS "Late Late Show" with Craig Ferguson that "things are really good."
Sheen then lifted his left hand to show his wedding ring. "That's a pretty good indication," the 40-year-old actor said Thursday.
Richards filed for divorce in March after three years of marriage. The relationship appeared to disintegrate publicly just months before Richards, 34, gave birth to their second child.
The couple were married in June 2002. They met while shooting the independent film "Good Advice" in 2000 and appeared in 2003's "Scary Movie 3."