There are many reasons why couples in the past may have stayed together longer. Some possible reasons include:
Social pressure: In the past, there may have been more social pressure to stay in a relationship, even if it wasn't happy or fulfilling. Divorce was often seen as taboo, and people may have felt that they had to stay in a relationship for the sake of appearances or social standing.
Lack of options: In the past, people may have had fewer options for finding a new partner if their current relationship ended. This may have made them more likely to try to work things out with their current partner.
Different expectations: In the past, people may have had different expectations for their relationships. They may have been more willing to compromise and work through difficulties in order to maintain their relationship.
Limited access to resources: In the past, people may have had limited access to resources such as therapy or support groups that could help them work through relationship difficulties. This may have made them more likely to stay in a relationship, even if it wasn't ideal.
It's important to note that these are just a few possible reasons, and there are likely many other factors at play as well.