Michael Buble admits the demise of his relationship with Emily Blunt was partly due to his insecurities and he says the split was the ''greatest thing'' to happen to him because it forced him to change.
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.
He said: "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.
"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."
Michael also admitted he has previously been in open relationships and though he enjoyed the sexual freedom to have more than one partner, he does think promiscuity between a couple is ultimately damaging.
He added in an interview with the Daily Mail newspaper: "I've been in open relationships. I liked them, but they don't work. Someone always gets hurt. I got hurt and I've done hurting. They are like communism; in theory a good thing, but when in place everything falls apart.
"Love has to be unbalanced. It's The Game. The man has to love the woman more so he's always chasing. My wife is playing it right. I'm like a stupid dog chasing after her car.
"If you really love somebody why would you want them to be with somebody else? For me it would be weird to feel another woman's lips.
"I'm not proud of how I've acted. I was reckless with other people's hearts."