Gwen Stefani recently revealed her split from husband of 13 years Gavin Rossdale was completely 'unexpected'.

And it has now been alleged that Gavin was cheating on the No Doubt singer for three years with their family nanny Mindy Mann, who was charged with looking after their three sons Kingston, nine, Zuma, seven, and Apollo, 20 months.

The new issue of  claims the Bush rocker initially denied having an affair with the child minder after another one of their nannies supposedly discovered messages and nude photos on the family's iPad and informed Gwen.

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Why it ended: It has been alleged Gwen Stefani and Gavin Rossdale split because the Bush frontman was having an affair with the family's nanny - Mindy Mann - she is pictured here with the singer in 2010, and the couples sons Zuma and Kingston

Explosive claims: The new issue of Us Weekly has made the claims, and says the couple's marriage imploded when the Voice mentor found 'explicit' photos and messages on the family iPad

MailOnline has contacted both Gwen and Gavin's spokespeople for comment.

Gavin, 50, is said to have initially brushed the messages off as 'flirtation', before allegedly confessing to adultery months later, the magazine reports.

It 'completely devastated her,' a source told Us. 'She was mortified, livid, and embarrassed.'

The supposed liaison is alleged to have lasted for more than three years, including the period when Gwen was pregnant with their youngest child Apollo.

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