The couple have split, their representatives confirmed, reported Us magazine.
"They both deeply care for each other and remain close friends. We kindly ask that the media respect their wish for privacy regarding this personal matter at this time," their representatives said in a joint statement.
Insiders close to the two said they very quietly and amicably ended their relationship a few weeks ago.
"They made the decision to part ways because their conflicting touring schedules would keep them apart over the next year," said a source.
In the months since, the duo have appeared together onstage at various concerts and on the red carpet at the 2015 Grammy Awards. They also often refer each other on social media.
Sean tweeted on April 4, "Just know I love u and I care for ya." Grande echoed his sentiments on April 16. "Love u babes the most," the "Bang Bang" hitmaker wrote. "You just can't imagine.