In this day and age, everyone is born with their soul mate's name on their wrist, in fancy black calligraphy. Then, they spend their life looking for that person and once they find them, they have to spend time with each other. If someone goes more than a week without seeing their soul mate, they start to get sick—very sick. After two weeks of not seeing each other, they most likely will be hospitalized; it's just the way we learned. No one knows how it works though.