Lovato broke the news on Instagram by posting a screenshot of a note they wrote together.
“This was an incredibly difficult decision for both of us, be we have realised more than anything that we are better as best friends,” they wrote.
They also thanked all of those who supported them during their relationship.
This is a sad time for Lovato following the passing of her great-grandmother last week.
“I'll miss your smile, your wittiness, painting your nails and your kisses,” she wrote as a caption for an Instagram photo of her and her “Mimaw” sleeping side-by-side.
Lovato is teaming up with Nick Jonas for her Future Now tour.