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Crooner and sexy MF Michael Buble has spoken out about his split from actress Emily Blunt back in 2008. The singer signed his autobiography Onstage, Offstage for fans at Waterstone’s in London, England today.

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“It ended through both of us being young and naive and making silly mistakes. It was about me looking in the mirror and saying, ‘Michael, wake up.’ I never lived in the moment, not ever. It was out of insecurity and me worrying what would happen. I thought, ‘You know, you could like yourself more.’ I’m not embarrassed to say this. I f***ed up.” Michael told the Daily Mail.

“What happened after the ex was probably the most important time of my life. When we were done I was devastated. I took time to do therapy. I had to…I knew if I didn’t change I would never be happy or content in my own skin with who I was. It was the worst thing that ever happened to me and the greatest thing that ever happened to me.”

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The 36-year-old singer – who is now married to Argentinean model-and-actress Luisana Lopilato – believes the demise of his three-year relationship with the actress in 2008 was his own fault because of his insecurities and he says the end of their engagement forced him to change.