well Juliet is partially responsible for the death of romeo because when he heard she was dead he killed himself only because Juliet hadn't told him that she wasn't actually dead. and romeo is partially responsible for Juliet's death because he killed himself and when Juliet saw that he was dead then she killed herself. also they are both responsible for their own deaths because they didn't tell each others parents that they got married because if they had then Juliet wouldn't have had to pretend to be dead so neither one of them would have had to kill themselves.
