If I am understanding the question correctly, you are examining the different relationships in this novel and seeing what light they cast on Victorian society. I guess one way to approach this question then is to think about love and marriage and how the different relationships show us different aspects of these themes: Charlotte Lucas and Mr. Collins, Lydia and Wickham, Jane and Bingley and finally Elizabeth and Darcy. You also will want to consider the examples of marriages that we are presented with: Mr. and Mrs. Bennet and Mr. and Mrs. Gardiner.
However, focussing on Darcy and Elizabeth, both have to overcome personal failings to arrive at love and marriage, in the form of his pride and her prejudice. Through confronting and overcoming these character failings they change considerably, and particularly in the last third of the novel, we witness a great change in their characters, with Darcy losing his cold reserve and pride (as observed in Lizzie's first trip to Pemberley) and Elizabeth losing some of her prejudice towards Darcy and discovering his true character. Compared to Jane and Bingley, theirs is a marriage of opposites, with her liveliness and pleasure in idiosyncracies finding a happy match with his decency and gravity. They help moderate each other, and their mutual knowledge of the other's weak points, the novel suggests, makes their marriage the strongest of all.
Behind all of this though, and perhaps most clearly articulated through the example of Charlotte Lucas and Mr. Collins, is the desperate state of women in those days who could only find status and recognition through society through marriage. This explains why Charlotte is so desperate to marry even someone like Mr. Collins - as this is the only way to avoid her fate as an old spinster left to look after her parents in their dotage.