The singer is said to have found texts from another woman on the paparazzo's brand new iPhone.
'There were about a dozen from one girl, all sent on one day,' says a source. 'Britney lost it and started yelling. She was demanding to know who sent the texts and shouting, What's this about? You're cheating on me.
'Adnan said the girl was just a friend, but Britney got more and more angry. Then she told him, That's it. It's over.'
And in a fit of rage, Brit, 26, is even believed to have thrown 35-year-old Adnan's mobile into her swimming pool.
'Just before she told Adnan to go, she took the phone and threw it in the pool right in front of him,' the source tells The Sun. 'He didn't even bother trying to get it out of the water.'
Brit first hooked up with the Birmingham-born snapper in December.
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