Gwen Stefani may be airing grievances about her ex-husband, Gavin Rossdale, in her new single "Used to Love You."Stefani debuted the tune live on Saturday night during a performance at Manhattan's Hammerstein Ballroom, and the lyrics seem to point decidedly in Rossdale's direction. After 13 years together, Stefani filed for divorce in August 2015. Rumors of Rossdale possibly cheating surrounded the couple's split from the start.The single's lyrical bombshells certainly don't quell any of the gossip, either."Never thought this would happen / Gotta let it sink in you're gone," it begins. Calling herself "the best thing that ever happened to you," Stefani sings, "You just pushed me too far," and, "Nobody taught you how to love." But while Stefani cops to still crying about it, at least she's not the one now "lost."If the song is, in fact, a thinly veiled reference to Rossdale, it wouldn't be the first time Stefani channeled heartbreak into her music. Just ask No Doubt bassist and platinum-hair-poster-boy Tony Kanal. "Don't Speak" still gets heavy rotation whenever our romances — or, y'know, reliable hookups that never graduated past brunch — hit the skids. And from the buzz "Used to Love You" is already generating, Stefani may have just gifted us a bonus track for our go-to breakup playlists.