The 27-year-old Brit was previously engaged to her Alfie co-star Jude Law, but they split after his infidelity with his children's nanny was exposed in 2005.
Miller went on to date Welsh actor Rhys Ifans, but that relationship also ended in heartbreak before she moved on with Brothers & Sisters star Balthazar Getty.
The romance was mired in controversy as the married father-of-four reportedly cheated on his wife with Miller in 2008.
The on-off relationship has now come to an end, with Miller insisting she's happy to be single - and she is adamant she won't let her past romances put her off dating actors in the future.
She tells Britain's GQ magazine, "If I meet an actor, I'm not going to deny the feelings I have for him because it's going to be perceived in the wrong way. How can anyone's head affect their heart? That's not in my make-up.".