Answer:
Because of Edward's choices.
Step-by-step explanation:
One of the reasons why Colonel Brandon's story is so difficult is because of the situation Edward is in. Colonel Brandon's describes the suffering and tragedy that Eliza experienced after she was forced to marry the wrong person. Most of these tragedies would have been avoided had she married the colonel. Edward is now in a similar situation with Lucy Steele. While he is engaged to her, it is unclear whether the marriage will take place. If it does not, she might have a similar fate to that of Eliza.