“High Society” star Tinsley Mortimer has split with boyfriend Brian Mazza, a partner at Paige Management, which owns The Ainsworth and Axe Lounge in Southampton. The socialite and the club owner had lived together since February and broke up in May. Mazza moved out but Mortimer kept the dog. Mortimer told us, “He was a great friend and the relationship ran its course. We were going to share Bambi month to month, but he thought it would be too hard for him. I am dating and looking forward to some trips in Europe this summer.”