Life & Style can exclusively reveal that Justin Bieber affair with Rihanna is what caused his split with Selena Gomez! After two years of dating, Selena found out that Justin had cheated on her with the songstress in the early stages of their relationship
 
“It has devastated her,” a friend of Selena and Justin’s reveals in the new issue of Life & Style. “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’s caused Selena to question their entire relationship.”

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After flirting at a basketball game in LA on Feb. 20, 2011, the friend tells Life & Style that he and Rihanna hooked up.
 
Though Justin and Selena, who have been dating since late 2010, have been off and on in recent months as work kept them apart, this devastating piece of information caused her to break things off for good, says the friend. Now, “Selena thinks maybe they’ve been hooking up all along,” their friend tells the mag.

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An insider reveals that they spent time together in NYC while taping the Victoria’s Secret Fashion Show in November 2012. “During breaks, they’d sneak away to the Hotel Giraffe,” the source tells Life & Style. “They were alone — their security made sure of it. Hotel staff blocked off the entire floor for them.”

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A rep for Justin denies anything physical happened with the “S&M” singer. And the friend believes he’ll never confess and let down his fans. “Justin would never admit to it; he would never tell anyone he messed around with Rihanna.”
 
For more on Justin and Rihanna, pick up this week’s issue of Life & Style, on newsstands now!