Erin Burnett is off the market! The brainy beauty, who has garnered male fans on Wall Street with her financial reports at CNBC, has been flashing a diamond ring as she promotes her new CNN show, “Erin Burnett OutFront,” which premieres on Monday. Burnett stepped out with her fiance, Citigroup exec David Rubulotta, at a launch party for the show at the Museum of Arts and Design at Columbus Circle on Tuesday, where she was feted by Piers Morgan, Anderson Cooper, Joy Behar, Ali Velshi, Jeffrey Toobin, Pat Kiernan, Ken Jautz, Mark Whitaker and Jonathan Wald. Burnett gushed that Rubulotta proposed last month.