SELENA GOMEZ AND THE WEEKND HE DID THE BREAKING UP

Multiple sources connected to The Weeknd and Selena tell us, their relationship had been fizzling out since Summer. They had rarely seen each other because of his touring schedule and her shooting schedule. They started talking less frequently on the phone.

We're told Abel enjoyed being single before he met Selena and felt unfairly tied down in a relationship that had lost its passion. Our sources say several weeks ago Abel called Selena, explained how the relationship was no longer working for him and then ended it.

Our sources say the 2 remain friendly and have even talked several times since the breakup.

As for Justin Bieber ... we're told he was not a factor in the breakup. Justin's apparent reignited relationship with Selena didn't start until after she and The Weeknd went their separate ways.

As for Abel ... he's not sulking. Check out our video shot Monday night. He's a quick rebounder.