The singer was spotted without her wedding ring over the weekend.
"They've been quietly and lovingly working on their friendship," the source added.
Another source told ET, "Ariana and Dalton’s friends have always been concerned by their whirlwind romance and felt their relationship would ultimately be short-lived. Their relationship has been rocky at different points, and they've had trouble making time for each other with scheduling issues."
TMZ was the first to report the news of the 30-year-old singer's split, noting that sources close to the couple say they've been separated since January and are "heading towards divorce."
Troubles between the two reportedly started even before Grande moved to London to film the Wicked movie, with TMZ also sharing that the couple tried reconciling a few months ago, but it didn't last. Grande and Gomez, 27, remain friends, and talk on the phone regularly, according to TMZ's source.
Speculation ramped up over the weekend, when Grande attended the Wimbledon men's tennis final between Carlos Alcaraz and Novak Djokovic alongside Wicked co-star Jonathan Bailey, notably, without her wedding ring on. Bailey is openly gay.
Grande and Gomez tied the knot in May 2021, five months after the singer announced her engagement. While the couple has kept their relationship relatively private, a source told ET in April that Gomez was supportive of Grande's major movie role. The GRAMMY Award-winning singer stars as Glinda, opposite Cynthia Erivo's Elphaba in director Jon M. Chu's two-part adaptation of the beloved musical.
"Ariana has been so focused, but Dalton has been there with her and supporting her behind the scenes," the source added.