Complex sentence: Benjie has deep pain, stemming from constantly dealing with his father having left the family and the fallout from his departure; exacerbated by Benjie's inability to get along with his mother's new boyfriend Butler (Paul Winfield).
Split into simpler sentences: Benjie has deep pain which stems from constantly dealing with the fact that his father left the family and the fallout since his departure. On top of it all, Benjie cannot manage to get along with his mother's new boyfriend, Butler (Paul Winfield).