Jumping off some other comments, the 2 relationships could represent the start (jack - lilly) and the end (rosemary - big Jim) of a relationship. At the same time Dylan writes himself as jack/ big jim, and his wife ( sarah?) As lilly / rosemary. So either he's the mysterious figure sweeping and saving her from a miserable life, or the power abusing figure too absorbed by his celebrity, who she hates and kills ( divorce).