Actually I don't know Selig much at all, and I never heard that song before, just googled it. I do get the impression though that it's their song, not a cover version. The Rammstein song is an entirely different song, not a version of this one, it just shares the title. The Selig song is about dealing with breaking up, the Rammstein one is about being in an abusive or at least pointless relationship of the "can't do with you, can't do without you" type. Their chorus translates to "Can't be without you, but with you I'm just as alone".