The on/off couple have reportedly broken up again after they had a disagreement over Justin not inviting the 21-year-old singer to his manager Scooter Braun's wedding in Canada on Saturday (05.07.14).
A source told the HollywoodLife.com: ''Scooter made it clear that he just wanted Justin [to attend the wedding] as that would allow the focus to be on their special day and not what Justin and Selena were doing.
''Justin obeyed Scooter's wishes which in turn got Selena upset and then got the ball rolling for them to fight and break up ... It all spiralled from there.''
However, the 20-year-old star didn't let his split from Selena ruin Scooter's lavish ceremony as he jumped up on stage twice to sing for the newly-weds.
Meanwhile, Justin and Selena's split comes as no surprise to their friends as the 'Baby' hitmaker spent America's Independence Day surrounded by other women on a yacht in Miami on Friday (04.07.14).
Selena, who secretly spent two weeks at the Dawn at the Meadows treatment facility in Arizona in January, is now being urged by her family to check into rehab again as she's struggling to deal with her heartache.
A source said previously: ''She is a mess over what Justin has been doing to her, and how he has played with her emotions.''
The pair, who first began dating in 2010, had a brief split in April amid rumours Selena was jealous of Justin's friendship with reality TV star Kylie Jenner, 16, but the hunk managed to win back his ex after showering her with gifts.
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