Her then-fiancé Jude Law apologized for an affair
last year, but Sienna Miller has her own issues with monogamy, she says in a new interview.
"I don't know, monogamy is a weird thing for me," Miller, who is still seeing Law, tells Rolling Stone
in its new issue. "It's an overrated virtue, because, let's face it, we're f–ing animals."
She says she was upset by the scandal – Law admitted he'd cheated with his kids' nanny – because it drew attention away from her acting. "Everything happened in the wrong order," she says. "You become very known for being someone's girlfriend, and all of a sudden there's all this hype and buzz for all the wrong reasons."
Miller, 24, who has been in Pittsburgh shooting a film adaptation of Michael Chabon's novel The Mysteries of Pittsburgh,
says she's already worried about getting older. "It's so hard for women in this business. And I want to be doing this when I'm 50."
She also says she "can't wait to have babies."
"Jude has three children," she says of Law, whom she met on the set of Alfie
in 2003, "and I have never tried to be their mum or anything, but I've had the benefit of living with them and loving them without
being the parent. But I love the idea of being a working mum and having my kid on the set."
Miller, who also stars as the waiflike Edie Sedgwick in Factory Girl
which opens in December, weighed in on the trend of thinness in Hollywood, telling PEOPLE she resisted dieting for the role.
"The director (George Hickenlooper) wanted me to (lose weight), but I can't work that hard and not eat all the food that I normally eat – and I'm a real pig!" Miller said Wednesday at the Pepe Jeans New Ambassador launch party in London. "He would come and try to snatch bagels out of my hands and I'd snatch them back."
However, with her demanding schedule she said she did shed some pounds. "I think with the amount of hard work I was doing, I lost a few pounds," she says. "But I've never tried to lose weight or gain weight in my life. I need my food to keep my energy up, so I can't really diet."