@maya54, yep. You’ve zeroed in on something some people really have trouble with: It’s not “nice manners” if it makes the other party uncomfortable.
Respect is wonderful, culture is important (believe me, I get it, I was raised in the south too), but if it’s received uncomfortably, then that too needs to be respected.
Whatever you like to be called, want to be called or don’t care what you’re called, just address it at some time with the S.O.!!! It is ridiculous that some of us spent years/decades not addressing an in law by anything because it was never addressed and felt uncomfortable to bring up.
You can do it formally or lightly - whatever your method of communication is. For my son’s wife at some point I noticed her calling us Mr or Mrs Abasket - and I said, “SIL - please just call us by our first name - we are fine with that and it is what feels most normal to us!!!” - it became a joke for awhile that she would use Mr or Mrs and I would have to reprimand her. 
Our oldest kid was born in Germany and for a while my parents thought they’d like to be Oma and Opa the German word for grandfather. But after we returned to the US about six months later they changed their minds. My father just became Grandpa and my mother became Gran(d)+her first name. (She got the idea from my cousins who had a Grandjoy in their life.) It was annoying that both Grandpas wanted to be Grandpa. My SIL took to calling my father Grandpa Hisfirstname which he disliked, but it really was easier to have some way to distiguish who was who.
As for in-laws my mother called her in-laws Mother M and Father M which I thought was a good compromise - a little more distant than Mom and Dad, but still acknowledging that they were family. My MIL gave me two choices “Mom” or her first name. There was no way I was calling her Mom though I loved her dearly, so first name it was. I think I’d been calling her Mrs. Last Name up till then, but mostly avoiding calling her anything.
What is it like in your work place? When I graduated from college at 21, it was normal to call colleagues and bosses of any age by their first names. Do your younger colleagues do that? If so, why wouldn’t your kids’ friends and SOs?
Also, why in 20 years haven’t you stepped in to help your wife communicate with your parents? Like “Hey, Mom and Dad, my dear wife doesn’t know what to call you, and it makes things awkward. What would you like to be called? And if you want to be called “Mom” and “Dad” but she is not comfortable using those names for people who aren’t actually her parents, what options would you consider?” You could solve this, I don’t see why you haven’t.
My husband and I have known each other’s parents since we were born ( our mothers were college roommates and friends long before we started dating). In that era of course we called adults Mr and Mrs. So the switch to their first names after decades was especially awkward and we both avoid calling them anything. Calling people who didn’t raise us any form of Mom or Dad was a nonstarter though. That’s just icky to me.
I don’t have any grandchildren on the horizon - and that’s fine, no hurry. But I already know what I’ll be called…
When my kids were little they loved to do imaginary/dramatic play with some of their stuffed animals. They created personas for the animals, names, voices, etc. When they played it was like the stuffed animals were the kids, my kids were their “masters” or adult figure - and therefore when they referred to me in their play, I was the grandma figure. Well the name they used then stuck - and they often call me that even now - it’s a nickname! It’s a form of “Grandma” - but in a silly way that has meaning to our family - I’m pretty sure that when and if the time comes, that will be how I’m called - and it will feel pretty natural to me!
@MomofJandL It is normal for people to just use 1st names in the workplace (Although a few others also speak the same way that I do). I just don’t and will say Ms./Mr. 1st name when I speak to someone that is old enough to be my parent which hasn’t been a big deal (I have worked most of my career in a pretty small town outside of Atlanta metro area so it has not been a problem to continue that tradition). In my 1st job, I was a supervisor of a man old enough to be my grandfather, and I called him Mr. Frank (his 1st name) which surprised him at 1st, but he knew it was a term of respect from me. When it comes to my wife not calling my parents anything, I didn’t notice that little fact for years until I heard my wife and my cousin’s wife talk about it about 10 years into my marriage. I asked my wife if she wanted me to say something and she said she was good with the way things were (both of my parents would have made a big deal about it and we would have had to go through the process twice since my parents are not together) and moved on but we don’t see my side of the family nearly as much as hers because we live much further away from my family … I definitely noticed it after that point and I have wanted to say something but I have respected my wife’s wishes .
@ChangeTheGame. We had a senior partner dress down a young associate from the South who kept calling him Mr Jones telling him that it was important that our clients saw the two of them as equals and not make him think that his work was being foisted off on a menial employee. .
@ChangeTheGame , as a late-middle-age woman – living in the south! – I would be so appalled if a work peer called me Ms. Firstname, except maybe as an affectionate joke (one time). At work we are peers. I have colleagues who are young enough to be my children, but when we’re working together on a project, we’re equals.
I can relate to @ChangeTheGame and his wife not calling the in-laws anything. It’s horrible to say, but I think I would feel more comfortable calling them “Hey, you.” than calling them Mom and Dad. So I didn’t call them anything until we had our first daughter. Then I began calling them by the Japanese term for grandmom and granddad which is Bachan and Jichan.
When we were first married, H had a tough time figuring out what to call my parents as his friends were calling them by their first names as they knew each other socially. He just avoided calling them anything until S arrived the following year. After that they were Popo & Gung Gung. If it needed to be clarified which set of grandparents, their 1st name went before that, so it would be HImom Popo & HImom Gung Gung, HIdad Popo & HIdad Gung Gung. It worked out fine. He still only refers to my folks that way and has never called them mom and dad, though I switch back & forth, depending on whom I’m talking to.
I wouldn’t call someone by a name that offended or upset them and I would always address someone as they preferred to be addressed… But I can only remember a couple of people saying they just preferred there 1st name over the years. But I am definitely getting older as there are maybe only 2 people in my office of close to 100 that are older than my own parents.
@chumom My wife has talked to others who don’t call their significant others anything. I always have thought that was weird because even when my wife’s parents hated me (and they definitely did not like me early on), I still called them Mr and Mrs. Last Name. But I was also not affected by their impressions of me at all, while my wife really wanted my parents to like her (it has taken 2 kids and entire marriage for things to just be “okay”)
I have raised my children to call our friends Mr and Mrs. When they were small, if someone told them to call them by their first name I explained that it was important to me that they call them Mr. and Mrs. Of course now as adults they get to make their own choice.
@maya54 your scenario made you uncomfortable, but your response made someone else very uncomfortable. Why does your preference for comfort supersede someone else’s preference for comfort. I will err on the preferences of the parent and if a parent tells me they prefer their child call me Mrs so be it. No skin off my nose.
My son told us at Christmas that his girlfriends parents want to be called by their first names. He recognizes that’s what is making them comfortable so he’s going with it. I told him that if the girlfriend would like to call us by our first names that is fine with us and he replied "that would make me uncomfortable "
“@maya54 your scenario made you uncomfortable, but your response made someone else very uncomfortable. Why does your preference for comfort supersede someone else’s preference for comfort. I will err on the preferences of the parent and if a parent tells me they prefer their child call me Mrs so be it. No skin off my nose.”
So if I prefer my child calls you by your first name you are fine with that right? Or if not, why is this a one way street??
Generally I think people should be called what they want to be called, but I don’t think anyone should be forced to call someone who isn’t their parents Mom and Dad.
When I was little I was friends with a family where the Dad called his wife “Honey” far more often than he used her given name. It stuck and her kids called her Honey as well.
We’re immigrant family (both us and kid’s SO, although from different countries/ethnicities) and were raised in a culture that we have a term for everybody that’s older than us (even siblings). I’m fine using first name at work or church, etc. But within family and potential family members, I’m not sure I will be comfortable and want to be called by my first name. My kid’s friends call us Mr and Mrs LastName. My daughter’s SO addressed his Christmas gifts to us as Mr. LastName and Mama LastName. I think my daughter uses these as well to address his parents.
“So if I prefer my child calls you by your first name you are fine with that right? Or if not, why is this a one way street??”
Yes, if you prefer your child calls me by my first name I am fine with that. As I said, I will defer to the parents wishes for their minor children.
My point was, that in your scenario their was no avoiding an uncomfortable situation. Someone was going to be uncomfortable. It’s not a one way street , and I don’t know who gets to decide which party should be uncomfortable. That is why I choose to defer to the wishes of the parents.
In @maya54 's case, though, the parents wanted their kids to call her by something that wasn’t her name.
If Maya Smith marries John Paul Jones, but keeps Smith as her last name -
She is not Mrs. Jones
She is Not Mrs. Smith
Neither of those names is even correct. Some other kid’s parents don’t get to make up a name for her.
Now they can ask their kids to call her Miss Smith, or Ms. Smith, or Miss Maya, even though she doesn’t like that name.
Or they can teach their kids to call people what they want to be called and are comfortable being called. Maya, for instance.
At work if everyone calls me Jane but this one guy keeps calling me Mrs. Fonda, than that one guy is making a big deal about my age and it would annoy me.
Exception is that as @mathmom mentioned, asking someone to call you Mom or Dad when they are not comfortable doing that seems rude. I would never have used those terms for my in-laws, and wouldn’t want future SIL/DIL to call me Mom. If they didn’t like calling me Jane, we’d have to come up with an acceptable alternative. It’s better if the parent-in-law initiates that discussion, probably with their own kid first (Tell Ted to call me Jane, or let me know if he’s not comfortable with that) rather than expecting the future SIL/DIL to initiate it.
My kids attended a school at which all teachers, including Head of School, were called by their first names; I found that very uncomfortable. However, in many ways it seemed to encourage a more approachable relationship between students and teachers
Agreed with all the comments about professional parity. On the personal side, when there’s a different preference in what to call someone I give more weight to the side that wants less intimacy. That usually tends to the more formal, which I’m not, but my personal lens has me feeling like it’s pushy otherwise.
I always had my sons’ peers, from toddlerhood, use my first name. When other parents taught formality, I went with that, though my long and difficult last name had me encouraging the merciful option of “Mrs. B.” That’s what I went by as a room mom in DS2’s first grade class. One of the students called me by my first name and the teacher corrected him. He said, “But it’s her name.” To which I said, “Sure it is, but your teacher has this rule and ‘Mrs. B.’ is my Nom de Classroom.”