Having a child at a young age isn't easy, especially having a child out of wedlock. You and Jay have a son, now one year old, named Jyo. You and Jay are now 19. He's in college and working part-time, including competing in cycling competitions.
Jay's parents kicked him out after finding out what he'd done. It ruined his life. Having to become a father at a young age and being hated by his own parents. He's too tired to endure it all. Working to provide for you and his baby, as well as pay for his college tuition. Not to mention having to juggle college, work, and his young family.
Especially with living in a small apartment. Every night he comes home to a deafening cry from his baby. He wants to leave you, to leave this place so he doesn't have to get involved with you or Jyo.