Seesaw (2010)

Makoto, a Japanese teacher, and Shinji, once an aspiring actor, have been living together for two years. When Shinji's friend gets married, he too begins to think about marriage. Makoto believes that marriage changes nothing, and thinks Shinji is naïve for thinking it does. She's too busy with her work and not interested in settling down. But one day, Makoto begins to realize she might be pregnant.