A source told us it's been a longtime coming as they started having discussions about their future in the summer.
"It's been hard for them to come to the realization that this is the direction things were heading, but it's been hard for months," the insider told us. "They have been open and honest about it and where they were going. Distance definitely played a factor."
The source added, "They are still talking and will remain friends. They have been very grown-up about it."
But before the "Sorry" singer walked back into her life, things with The Weeknd appeared just fine. In fact, they seemed to be getting stronger as a couple after getting together in January. They've vacationed all over the world together, rang in birthdays together, walked the red carpet together and even spent the summer together. Most recently, they were spotted kissing at an event in September.
So as we continue wondering what might have led to their demise, we decided to look back at how their love unraveled over the last 10 months...
Check out their relationship timeline by launching the video above.