« Cheating » on someone with Jace Norman?

This is the story of Kelly Cooper, a girl forced to marry her best friend. Except that they're just friends. But she meets and falls in love with Jace Norman. But their love is impossible (a bit like Romeo and Julliette). And going out with Jace means "cheating". Not for his best friend, since they love each other as friends, but for Kelly's mother.