The 'Bad Romance' hitmaker's former friend DJ Brendan Sullivan claims her relationship with Luc was volatile because of his disrespect of her sound and the singer realised putting her career first would make her personal life suffer.

Brendan said: 'Luc didn't like pop music, so he basically didn't respect anything she did.

'The concept she came up with is the she's working hard on her music to impress this guy, but the harder she works on the music, the more it will take her away from this guy. She wins and loses either way.'

Although the pair stayed together, Luc came to realise having a famous girlfriend was not an instant ticket to fame for himself.

Brendan explained in Maureen Callahan's new book 'Poker Face: The Rise and Rise of Lady Gaga': 'He thought having a girlfriend with a record deal would be all VIP shows and instant status.

'He didn't know that music was an actual profession and he would have a busy girlfriend who was always out of town or on her Blackberry.'

Despite their troubles, Gaga's former tour manager David Ciemmy believes the pair will always be involved.

He said: 'She just has always had a thing for him, and he knows it and he took advantage of it.'