Sources close to Paris tell TMZ ... she decided it was time for her to go solo. The breakup, we're told, was amicable as neither holds any anger or ill will. Our sources say the relationship just ran its course and it was something that just needed to happen.

As for what Paris will focus her attention on now ... our sources say she's been really invested in her music. She's been so invested, she's been at the studio practically every day. We last saw her out and about last week ... looking happy, mind you.

Paris, as you may know by now, had also been working on a Facebook Watch docuseries dubbed "Unfiltered: Paris Jackson & Gabriel Glenn." The 6-part docu-series debuted on June 30 and its final episode airs tonight. Paris and Gabriel have been dating since November 2018.

Over that time, they were usually out together ... often at L.A. music joints for Gabriel's gigs.

As we reported, she played best roadie GF for his gig at the Viper Room. And, remember ... Gabriel also stood by Paris' side during one of the most turbulent moments in her life.