LOS ANGELES, June 10 -- On Saturday night in Oakland, Ariana Grande opened her first tour in six and a half years to an arena that sang every word back at her. By Tuesday, the public learned that the relationship running underneath the most scrutinized chapter of her career had quietly ended. The two facts are doing a lot of work on each other.

Grande, 32, and Ethan Slater, 34, have split after nearly three years together, People first reported, describing the breakup as amicable. ABC News reported that representatives for both did not respond to requests for comment, and neither has said anything publicly.

The silence is part of why the story lands the way it does. This was never a private relationship in any meaningful sense. It began...