It is my understanding that the divorce rate is calculated by the simple formula of:
Number of divorces/Number of marriages
If we were to use the same formula for the death rate, we would have have:
Number of deaths/Number of births
As far as I know, the death rate for humans is 100%. So right from there this idea doesn’t make much sense.
Now consider that we have 10 couples which are married on January 1.
One couple divorces, and each partner marries again on February 1. They each do this 4 more times. Maybe even re-marrying each other once or twice.
At the end of the year we have 20 marriages and 9 divorces. Is the divorce rate really 45%?
The divorce rate is much more a reflection of the instability of individuals within a marriage, not the institution itself. In this case, two individuals out of 20 were unable to maintain a stable relationship.