Wickham’s affection for Lydia was just what Elizabeth had expected to find it – not equal to Lydia’s for him. She had scarcely needed her present observation to be satisfied, from the reason of things, that their elopement had been brought on by the strength of her love rather than by his; and she would have wondered why, without violently caring for her, he chose to elope with her at all, had she not felt certain that his flight was rendered necessary by distress of circumstances; and if that were the case, he was not the young man to resist an opportunity of having a companion.
– Jane Austen
Pride and Prejudice, Chapter 51. Here Elizabeth is thinking about the elopment of Wickham and Lydia. She figures out that Wickham did not elope and marry Lydia out of true love but because of "distress of circumstances" (he owed a lot of money locally) and "an opportunity of having a companion" (he is a serial sexual predator). The elopement was also driven by Lydia’s strong infatuation for Wickham.