That has never been the norm in the United States. If you look at early marriage and birth records, a remarkable number of first children were born suspiciously shortly after their parents' marriage.
Even in the 18th century, it would be extremely unusual for a couple of 28 and 30 to have completely abstained from all personal contact.
I never argued that all persons held to that standard, nor did I say anything about the U.S.; that custom held strongest in societies which practiced arranged marriages—and those societies are far fewer now than they were even 1,000 years ago.