On Oct. 23, Brad Pitt’s girlfriend, Nicole Poturalski, was spotted back with her husband, Roland Mary, enjoying a night out with friends in Berlin. But model’s open marriage with the German restaurateur, 68, doesn’t seem to bother Pitt. Despite the complicated circumstances, the actor, 56, is “happy to be living in the moment” with Poturalski, 27, whom he’s been seeing since summer, a source tells Us. “He feels no pressure to do anything. It’s the perfect arrangement for him.”…