Looks like Rihanna is caught in a love triangle with the ex and the next. Word is Chris Brown (who has a girlfriend) has sent Ashton Kutcher a warning about dating Rihanna. He allegedly told their mutual friend Diddy to tell Ashton stay away from Rihanna and he ain’t playing! Ashton thought he was getting punked thinking Breezy was joking but Diddy insisted Chris Brown was dead serious. Wow….Rhi Rhi got’em fighting over her Birthday Cake….