Owen Gleiberman Chief Film CriticLucy (Geraldine Viswanathan), the heroine of “The Broken Hearts Gallery,” is a soulfully flip 26-year-old New York art gallery assistant with a problem, or a fixation, or maybe we should call it a ruling passion. She’s so invested in her romantic relationships that each time one of them ends, she holds onto the mementos from it and treats the objects as if they were more important than the ex she broke up with.