The ex-couple, whose split was confirmed at the weekend, are apparently "not on great terms" following claims that he had phone sex with a former girlfriend during their relationship.
The Coronation Street actress has now banned George from seeing 13-month-old Pip, leaving the 'Warzone' singer "furious" at having lost "one of his best mates".
"He's not on great terms with Michelle at the moment, especially after the whole sex text thing," a source told The Mirror.
"She won't pick up the phone to him and has made it clear through the small conversations they've had he hasn't got a chance of visiting his pup."
The insider added: "He's absolutely gutted about it, he had grown so close to him and feels like he's lost one of his best mates... He loved that dog and is furious that even though he splashed the cash on it he'll never see it again."
George and Keegan got together in December 2010 and were engaged just six months later. They ditched their plans to marry in April this year before splitting for good.