I think this to be true. My parents are miserable but they stayed together for the kids (us) and what was expected of them.

My grandparents all died when I was relatively young, I never knew my paternal and material grandfathers and only had a short interaction with my paternal grandmother.

I would think they'd all be unhappy. The division of labor where the women in my family were to raise the young, cook, clean, etc for their entire lives must've driven them bonkers.

The men were all borderline alcoholics which, to me, is indicative of not only substance abuse problems but I believe unhappiness.

In general I think both men and women were unhappy in their marriages and the only thing that held them together, IMHO, was the religious mandates so they could get into heaven. If you ask me, heaven is already here. It's the world we live in.