“Something changed then, since the 50’s, early 60’s when I last had contact with anything Catholic”
Nope. It was written about even then. Look it up.
Catholics could always divorce—they used to need to discuss it with their pastor, who would inform the bishop, before they did it, but they could divorce.
What Catholics can not do is to remarry unless their first marriage has been determined to have been null (commonly known as “getting an annulment”). This was the case before V2, and is the case now.