It is rather convenient for the Pride and Prejudice storyline that Mr. Darcy was an orphan. The influence of family wasn’t very strong on his side (other than Lady Catherine’s vocal disapproval); for the most part, he was free to do as he chose.
Lady Catherine said that he was promised to her daughter, Anne. She purports that Lady Catherine and Darcy’s mother had planned this union from their births. With Lady Anne Darcy deceased, Lady Catherine has no one to back her up, and Mr. Darcy is free to disregard her claim.
We know very little about Darcy’s parents. Mr. Darcy the elder was an “excellent” man who seemed benevolent and kind. He sponsored Wickham’s education and was kind to his servants and tenants. He valued duty and honor and responsibility. Had he survived, I wager Mr. Darcy would have been very involved in selected (or, at the least, approving) Darcy’s choice for a bride.
I have always wondered if Darcy would have been permitted to marry Elizabeth if his parents had survived. Would they have allowed him to marry so beneath his station in life? Would they have wanted him to marry his cousin Anne? Would they have approved of Elizabeth, both her situation and her personality?
Obviously, there are no answers to these questions, for Jane Austen (in her wisdom) didn’t burden the story line with these scenarios. But part of me (the un-romantic part) believes that, if Darcy’s parents had survived, he would not have married the wonderful Elizabeth Bennet.