Blake Shelton will be the first to tell you that being a coach on “The Voice” changed his life in more ways than one. In this week’s “Sunday Sitdown,” the country music superstar opens up to Willie Geist about how that show not only exposed him to millions of new fans, but also introduced him to his current girlfriend, Gwen Stefani, at a very difficult time in his life. The Oklahoma native also chats about the early days of hunting for record deals as a teenager in Nashville, and what it’s like returning to Music City to open up his new bar and music venue “Ole Red.”