Twenty-year-old actress-turned-singer Selena Gomez allegedly dumped the 'Baby' hitmaker last week almost two years after going public with their relationship in February 2011 because she couldn't trust him when they weren't together.
A source told People magazine: "She broke up with him about a week ago.
"With them being apart so much it got complicated. She had some trust issues. It's not easy, but the relationship needed to end."
News of the couple's split broke on Friday just hours after Selena posted a picture on twitter of a photograph of Justin with Hungarian Victoria's Secret model Barbara Palvin in the background.
The Canadian popstar, 18, was spotted on a date with the 19-year-old model in New York earlier this week.
The pair - who met when Justin performed at the Victoria's Secret show in the city on Wednesday - enjoyed a trip to see the Lion King on Broadway.
The break-up is surprising as Justin recently revealed he was proud to have Selena by his side.
He said: "I never make [Selena] separate from me because I don't want her to ever feel like I'm ashamed of her. Because I feel like a lot of guys do that, especially in the business. They don't want to be seen with the girl, so they'll make them ride in separate cars. They'll do that 'get away' stuff. [Selena and I] get away together."
- BANG! Showbiz