I think it means a girl fell in love with someone else because of who they truly were. However, that person changed, making them their downfall, their sweetest downfall. Regina says " I loved you first" meaning, I loved you before you changed. Before, you cut your hair ("your hair was long when we first met), before you changed your personality and the thing that drew me to you changed. It means, now Samson, her former love does not care to contact her. He stays in bed, doesn't care to see her. All they had before he changed is forgotten about and erased. She thought what they had was special, like the brightest star, when really, the true light attracting them had worn out long before. He later comes back to her because he realizes his faults and what he had done wrong.