I've been married 31 years and have experienced the same. One receptionist in the kids secondary school was very adamant that I am Mrs DHSurname. I had to write in, as verbal requests didn't work, to ask for my name and title to be corrected for each of my 3 dc, even though it was all part of the same record in the database and I had filled in the application form with my correct name and title when applying for each dc. Surely the logical thing to do when adding a record to the database is to actually use the data on the form rather than unilaterally deciding that the mother, who may or may not be married to the father, is Mrs DHSurname?
Bil still addresses everything to Mr and Mrs DhInitial DhSurname when posting anything to us. He seems to take it as a personal insult that I didn't change my name to that of his brother.
Sports coach, who insisted on titles for himself and parents, repeatedly using the wrong surname despite numerous corrections. He eventually got it.
School applications to multiple secondary schools (different system here in Ireland), all bar one addressed responses to Mr and Mrs DhName, despite my name and title being clearly written on the form.
These are just a few instances. It gets very tiresome. To be honest, when I got married I had assumed that by now this would no longer be an issue but it seems to be just as bad as it ever was.