Sources close to the former couple tell us AG and PD split this weekend, with both parties acknowledging that it simply was not the right time for their relationship to take off. We're told the two still have love for each other, but things are over romantically.

Ariana and Pete announced their surprise engagement earlier this year in June -- just a few weeks after they were reported to be just casually dating. TMZ broke the story ... Grande's engagement ring cost right around $100k.

Grande's recently expressed she was going through a rough patch, tweeting a lot of personal messages and saying she needs a break from the public spotlight and asking "can i pls have one okay day. just one. pls."

As for Davidson, he's continued to appear on SNL, even mentioning his former fiancee in a couple sketches. The last time we saw them together was just last week.

Our source says while things may be done for the couple for now, the two aren't ruling out the possibility of anything in the future.