Topper Mortimer seems to be happily separated from wife Tinsley Mortimer. On Tuesday night, the blue-blooded banker was cheerfully conspicuous in his gray pinstripes among the leather-clad bohemians packed into Rose Bar for a “secret show” by indie post-punkers Elefant. At one point, he laughed it up with hard-partying rocker Jamie Burke and his scraggly haired pal, the vice president’s nephew, Bloody Social guitarist Jamie Biden. The following night, Topper schmoozed with guests at the dinner at the new East Side Social Club for the dress collection of his little sister Minnie. But Tinsley’s mom, Dale Mercer, is as unhappy about the split as ever, a spy insists. She clearly wants her daughter to dump German Prince Casimir Sayn-Wittgenstein and get back together with her husband. Mercer was at Bar 675 the other night saying she still speaks to Topper every day and that the prep-school sweethearts are a perfect couple.