Umi de no hanashi (2006)

A girl named Kaede Fukino finds out that her dad is having an affair. When she questions her mum about this she gets more than she bargained for. She soon learns that her life has been a lie, her father actually has a different family and she is the result of an affair. Shocked by the news, she consults her friend Hiroshi Hirono who she secretly has a crush on about it and it draws them closer. Hiroshi himself is also struggling with some aspects of his life.