I think also.. not dying. In the past it was common for people to have multiple marriages but with no divorce, I wonder what the stats say about median duration over time?

It used to be you had to stay together no matter what. It is not that people inthe past would miraculously solve marital problems - they often just had to stay despite violence, abuse or simply sever partners disregard. Except prohibition era, acess to alcohol and gambling was easy. Prohibition itself passed because alcohol situation was very bad.

And it simultaneously used to be that women were severely disadvantage in workplace making a men practical necessity - no matter what the relationship looks like. That is not people solving problems for family sake.