searching for wedding info online has been very, um, educational:
"at parties, dinners, and other entertainments it is the privilege of the young man and woman who are engaged to be with each other more than they are with anyone else, but this does not mean that they should make themselves conspicuous by ignoring everyone else"
from: etiquette in public, 1924
"when speaking to a woman, who has gotten engaged, one does not say congratulations. it is considered an insult, equivalent to an insult as if she could not get a man"
"there is absolutely no room for dating others once you become engaged"
"it is only natural that a newly-engaged couple will feel amorous and affectionate and want to show it at every opportunity. everyone around them is conscious of how much in love they are, and don't mind expressions of joy, up to a point. public displays of affection or sexual activity may make observers very uncomfortable"
"when the ceremony is over, the question sometimes arises whether the bride is to be kissed by the bridegroom. we should leave its decision to the instinct of affection were we not solemnly warned by a portentous authority on deportment that 'the practice is decidedly to be avoided; it is never followed by people in the best society.'"
from: ladies of reenacting, the bazar book of decorum. the care of the person, manners, etiquette, and ceremonials, 1873, and polite society, at home and abroad, 1901