Julie Wagner has everything today's young woman thinks she wants: a successful husband who adores her, a baby on the way, a close circle of family and friends, and a career as a photographer that is about to take off. So why is she alone in Montauk in the middle of December? During the cold, stark days, Julie throws herself into capturing her artistic vision for an upcoming solo show, yielding works of deep passion and instinct; at night, she restlessly taps away at her computer, plagued by uncertainty about the impending trajectories of her life. When her neighbor, a prickly but brilliant composer-musician knocks on her door with an odd request, Julie ushers in a series of events that will bring her in contact with her buried hopes and fears, and force her to make choices she couldn't have fathomed. At once shocking and wise, In Montauk is a now-familiar story turned inside-out by a main character who can't help but put herself into the most uncomfortable position of all-confronting life's imperfect choices in the hopes of grasping one through which she can be true to herself.
Julie meets her new neighbor, Christian. She hangs out with him in the following days, shooting with him in spots around their area, making him her model for her shoots, etc. A sexual tension between them emerges at 37:50. At 41:23, after having a picnic on the beach, they kiss and proceed to fuck at her place. In the morning, her husband calls and she answers it while still naked from having sex with Chrstian last night. Her husband accidentaly hears Christian's voice over the phone and gets pissed, asking her what he is doing at their place at that very early hour. This leads to their temporary separation. Julie gets pregnant, I'm not sure who the father is, probably Christian, but her husband gets back together with her and accepts the child as his own.