Scooter Braun is dating actress Rachelle Goulding. The 43-year-old retiring music manager and the 38-year-old ‘Firefly Lane’ star – who previously dated ‘Gossip Girl’ star Chace Crawford, also 38 – have been hanging out at Napa Valley and the Stagecoach music festival in recent months and are said to be getting “very serious”. An insider told the New York Post’s Page Six column: “They have been exclusively dating for about three months now. “It’s very serious and he’s excited about it.” The entrepreneur – who worked with Justin Bieber, Ariana Grande and Demi Lovato during his career – recently…