"It feels like somebody else's existence," she said in an interview for ELLE U.K.'s May issue while looking back at that time in her life. "I can go and visit it and look at it, but it doesn't feel like my life. I can't quite believe that it all happened. And not to put it specifically on that one thing, but just the chaos of the entire decade is so far removed from my life now."
The two met in 2003 while working on the movie Alfie and got engaged in 2004. But in 2005, reports spread that Law had had an affair with his children's nanny. In a public apology to Miller released to the British Press Association, the actor said he was "deeply ashamed and upset" that he'd "hurt Sienna and the people close to us," adding that "there is no defense for my actions, which I sincerely regret."
Law, 49, and Miller, 40, broke up in 2006, rekindled their romance in 2009 and split again in 2011.
While Miller had appeared in a few movies and TV shows before her relationship with Law, she told ELLE UK she "was just catapulted into a totally parallel universe while being in love [with Law]" and would be hounded by the paparazzi.
"There was a lot of magic at that time," she recalled. "At first, it was kind of comical, but very quickly it became insidious and, yeah, scary. And my boyfriend [at the time] had been experiencing it for years and felt, understandably, a lot of hostility towards that kind of attention. So my initial reaction was the same."
These days, Miller is acting in Anatomy of a Scandal. In the drama series, she plays Sophie Whitehouse, the wife of politician James Whitehouse whose life changes after she finds out her husband has been accused of raping a colleague with whom he'd been having an affair.
Miller could relate to her character in terms of having her private life suddenly become public. When asked about the most interesting thing about her character, she replied, "It was familiar terrain, because I've experienced some of the things that she experienced. And the feelings were familiar. [But] her way of dealing with what's thrown at her is the absolute antithesis of what my way is. And so, in a kind of twisted, tourism sense, I just wanted to see how it would feel to react differently. I know that sounds weird because you'd think it would be deeply unpleasant to sit in that space."
In one scene, Sophie and James, the latter played by Rupert Friend, find themselves surrounded by photographers.
"Rupert also had experienced it," Miller told the magazine, "so those scenes weren't pleasant for either of us, but it was weirdly interesting to kind of step back in and...There is something cathartic, I suppose, about spending time in an ugly space that's familiar. And maybe reclaiming it? I don't know what the psychology of it is. But there is something where maybe you can substitute a memory with something else."
Miller is now dating model Oli Green. And while she told Porter magazine in 2016 she doesn't see Law, who is now married to Phillipa Coan, "that much," Miller, who has a 9-year-old daughter named Marlowe with her ex Tom Sturridge, also suggested they've remained on good terms. As she put it, "I care about him enormously."