WATCH: Gwen Stefani Sings 'Used To Love You' on 'Ellen'

Singer and Voice judge Gwen Stefani has let fans know how she feels about the end of her marriage to Bush frontman Gavin Rossdale with the release of her anguished new single "Used To Love You."

The longtime LGBT ally debuted the song a week ago during the encore segment of her New York concert. The internet buzzed with interpretations of the song's lyrics, which tell the story of one partner betraying another.

Though Stefani wears her bruised heart on her sleeve throughout the song, she gets in plenty of jabs at her ex, concluding fiercely, "I don't know why I used to love you."

An official video featuring a tearful Stefani singing plaintively into the camera quickly followed the song's debut.

On Monday, she performed the song live on television for the first time on the Ellen show, with host Ellen DeGeneres confessing Stefani first played the song for her two weeks ago in her bathroom.

Watch Stefani perform "Used to Love You" below:

"Used to Love You" is now available for digital download.