We didnt have large divorce rates until about the 1960’s when no-fault divorce became legal. No-fault divorce was the biggest reason why divorces have increased
Intermarriage increased when it became not only socially acceptable for a NON JEW to marry a jew, in many cases its seen as even desirable among non jewish women to get a jewish husband.
Look at both Donald Trump and Hillary Clinton, both gave their blessings when their daughters married jewish men. That would not have happend 100 years ago, both daughters would have been disowned