I think it's less about changing the name and more about feeling bad about making the partner call them by the new name, maybe? It's pretty normal to use an assumed name for celebrities, isn't it? But I doubt Lady Gaga's partners call her "Lady Gaga" at home, lol. But at an industry party, yeah, if they were to be like "oh yeah Stefani was saying blah blah" some people might be like "uh, who?"