EXCLUSIVE: Nicole Kidman 'Blindsided and Broken' After Keith Urban Nashville Cheating Allegations Erupt Following Nasty Split – 'She Was Trying to Save the Marriage'

Keith Urban brutally betrayed wife Nicole Kidman by shamelessly flirting with country cuties around Nashville for years, RadarOnline.com can reveal.

Since the crooner and the actress split, it's been revealed Urban has been cozying up with his bandmate, guitarist Maggie Baugh, as well as other country hotties.

"There's no sugarcoating the fact that Keith's behaved like a total jerk. He's treated Nicole like dirt at a time when she was most vulnerable," shared an insider.

Sources said after Kidman lost her mom last year, she desperately needed love and support from her husband. Instead, Urban had checked out of the marriage and took things to a whole new low by flirting with other women.

While it has been reported Kidman was blindsided by the split, other sources said Urban felt there was a "lack of intimacy between them because they spent so much time apart, leaving him time to seek comfort in the company of other women. It wasn't just Maggie. Keith was also fawning over other women, and he didn't seem to care that people knew about it."

Sources said Kidman was convinced, lyrics from Urban's songs – such as Love Is Hard, which stated, "It hurts when we fight... Callin' names and slammin' doors – and keeping secrets" – were his way of callously calling out their private texts.

Then, sources said, Kidman was shattered when she viewed video of Urban changing the lyrics of The Fighter – a tune inspired by his romance with her – in a recent performance to instead include Baugh's name.

"It goes without saying Nicole is devastated and humiliated," a source said.

Another insider added: "It seemed incomprehensible to her that the love of her life would be capable of such cruelty."

As RadarOnline.com reported, Urban recently moved out of the Nashville mansion he shared with Kidman and their two daughters.

But, according to insiders, the marriage imploded years ago when Urban got fed up with Kidman's steamy onscreen clinches with younger actors, while her pals accused him of being insecure.