Denise Richards was married to Charlie Sheen for four years. It "aged her terribly".

As Denise Richards and her best friend Patrick Muldoon chatted over lunch, the Real Housewives of Beverly Hills star came to a conclusion that surprised precisely no one: “My ex-husband’s aged me terribly I think,” she mused.

That ex-husband, of course, is Charlie Sheen.

In the segment on Real Housewives, Richards recalled an unusual Thanksgiving dinner she shared with Sheen and a sex worker he brought along to the occasion.

“Charlie came over for Thanksgiving for dinner a few years ago, and he had a hooker in the car in the driveway,” she said. “He was afraid to tell me. ‘Uh, you know, well, she’s in the driveway. Is it OK if she’s in the driveway?’ I said, “Ugh, I’ll set a f**king plate’.”

Richards, 48, and Sheen, 53, were married from June 2002 to November 2006. They co-parent (not always easily, Denise says) their daughters Sam, 15, and Lola, 13, after going through a nasty split and custody battle.

Richards and Sheen met in 2000 while filming Good Advice, but they didn't begin dating until 2001 after Richards appeared on Spin City.

By their second date Richards said she knew Sheen was "the one".

“I knew that this is the one, but I wouldn’t tell him that. I didn’t want to scare him away by saying, ‘You’re my future husband!’ and have him run for the hills,” she told People.

Sheen proposed on Boxing Day 2001. During their engagement, Sheen had Richards' name tattooed on his wrist and after their wedding on June 15, 2002, Richards decided to get a similar one for him - don't stress, she's since had it covered.

During their marriage, Richards and Sheen continued to work together when Richards took on a recurring role on Sheen's sitcom Two and a Half Men.

In March 2005, while seven months pregnant with their second daughter Lola, Richards filed for divorce. They briefly reconciled after Lola's birth, but a year later in April 2006 she filed again.

The divorce was... well, it was one of the messiest divorces we can recall.

According to the Daily Beast, in 2006 during an intense custody battle, Richards obtained a restraining order. She claimed Sheen threatened to murder her and watched “disturbing porn”.

“I told the Respondent that if the Respondent proceeded with his threats to take me to Court over the children for overnight visitation, that I would have to tell the truth about what he had done. He told me that ‘I Will never get to Court because I will be f**king dead!’ He told me to enjoy my parents ‘while they are still around.’ I took this to mean that he was not only going to do me harm but also do harm to my parents,” Richards explained in the filing.

Since the divorce, Richards and Sheen's relationship has regularly gone from toxic to amicable to even more toxic.

Sheen went on to marry Brooke Mueller in 2008. They divorced in 2010 following allegations of domestic abuse and in 2012 and 2013, Richards acted as a temporary guardian to their twin sons, Bob and Max, while Mueller went to rehab.

"Brooke knows anytime, and Charlie, that any time they need help with the boys, that I'm there," Richards told Access Hollywood in 2011.

"They're our family and they're Sam and Lola's brothers and I can't imagine growing up without my sister, so anytime she needs help, I'm there for the boys... I know it doesn't seem normal, but it is our normal. They're little kids and I love children, and like I said, it's our daughter's brothers, so I can't say no."

In 2014, Sheen dated former porn star Brett Rossi and kicked Richards and their children out of the mansion he bought for them in his gated community. He also announced on Twitter he was going to reduce the US$55,000 he paid her in child support.

In 2016, Richards sued Sheen for raiding a $7 million trust that was meant for their daughters and for evicting them from their home.

Despite the challenges, more recently Richards and Sheen have worked hard to have a civil relationship.

She told PEOPLE earlier this year that she had no regrets about their relationship, or the more-than-a-decade of drama that followed it.

“I was never bitter about my divorce,” she said. “Going through everything, it changed me. But I love life and I’m a glass-half-full kind of person. And I did my best to rise above it.”

“No matter what happens, Charlie can call me at any point,” Richards added. “I don’t see our relationship as a failure. It’s a journey. It went a different way than we anticipated, but that’s okay. And I will always be a good friend to him.”