bieberrihanna020613.jpg No wonder Selena Gomez dumped him!

Apparently, the Spring Breakers actress found out that boyfriend Justin Bieber cheated on her in the early stages of their relationship with none other than Rihanna!


"It has devastated her. It really cut like a knife because it happened in February of 2011, when Selena and Justin had been dating for months and were falling in love. It has caused Selena to question their entire relationship," a source tells Life & Style.

Although the pop star and his lady love have been on and off in recent months, this piece of news was the straw that broke the camel's back.

"Selena thinks maybe they've been hooking up all along," the source adds. Her suspicions might not be wrong, either!

JB and RiRi reportedly spent time together at the Victoria's Secret Fashion show taping last November. "During breaks, they'd sneak away to the Hotel Giraffe. They were alone - their security made sure of it. Hotel staff blocked off the entire floor for them."

We wonder what Chris Brown has to say about all of this!