The Wanted singer, 25, has revealed that his 'problem with drink' was to blame.
Speaking to The Sun today (November 9), Max said: "I had a real problem with drinking too much and that was, without doubt, the downfall of our relationship."
He goes on to say that Michelle, now 26, called off their engagement three months before the news of their split went public because of his alcohol consumption.
He says: "I was drinking more to forget the fact I was with someone who wasn't making me that happy.
"Michelle is seen as Britain's Sweetheart nowadays, I understand it might have looked as if there was something to hide, [but] there was no betrayal in terms of cheating."
Coronation Street actress Michelle and boyband member Max got together in late 2010, before he popped the question with a £10,000 ring in April 2011.
She is now engaged to former TOWIE star turned TV presenter Mark Wright, while Max has been linked to a number of women including TOWIE's Lucy Mecklenburgh and Lindsay Lohan.
He is currently loved up with model Nina Agdal, who he recently described as "the most beautiful girl I've ever seen".
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Watch the video for The Wanted's 'We Own The Night':