The Mamma Mia! beauty spent two years in a long-distance relationship with her British co-star Dominic Cooper, before the pair split and she moved on to a short-lived romance with Ryan Phillippe.
The actress admits she is currently enjoying being single, because men are such hard work.
She tells Britain's Daily Mirror, ""I got my heart broken pretty hard. It changes you a little bit every time you either break someone's heart or get your own broken.
""For the first time in my life I'm really happy to be unattached because I realise there is so much responsibility to having a partner. I would just be with boyfriends for a couple of years at a time and after the last one, I really value my independence.""