The ballad of Blake and Gwen plays on. And this time, it's a duet.The country crooner opened up to Entertainment Tonight about the track he wrote and recorded with girlfriend Gwen Stefani, calling it "as good of a song as I've ever written in my life."He also got a little gushy about his new writing partner and the fact that they broke out of their comfort zones to create the track, which is titled "Go Ahead and Break My Heart."“[The song] is very personal for us both because, you know, we obviously have this bond that is remarkable together,” Shelton explained. "But the fact that we wrote a song together... I know that I don't co-write that much, because I'm very insecure about it I guess. And [Gwen’s] kind of got her circle of people that she writes with. But for us to reach out to each other as writers, it may never happen again, who knows."Stefani was actually the one to leak the fact that she would be appearing on Shelton's upcoming album, If I'm Honest, which is set to debut May 20. She tweeted a photo of the record earlier this week. Hopefully, we'll get to hear the song long before then — but we've already got a pretty good idea of what it's about. Both Shelton and Stefani have gone through high-profile divorces in the last year — so if anyone was going to come out with a heartache song this spring, it makes sense that it would be these two.