They were always moving from place to place in quest of a cheap situation, and always spending more than they ought. His affection for her soon sunk into indifference: her’s lasted a little longer; and in spite of her youth and her manners, she retained all the claims to reputation which her marriage had given her.

– Jane Austen

Pride and Prejudice, Chapter 61. After the marriages of Elizabeth and Darcy and Jane and Bingley, we learn that their lives progress happily, but this is not the case with Lydia and Wickham. They lead unsettled lives, moving from place to place. With Lydia married to a waster, they continue to squander money and live beyond their means. Like the money, their affection towards each other also soon disappears.