First of all Congratulations!
I dearly love my in laws of 35 years (FIL passed away last spring), but have always called them by their first names. I call my own parents “mom” and “dad”. I also can not imagine calling them Mr and Mrs last name which sounds kind of cold and formal to me.
My son’s girl friend calls me us by our first names, I think. In any event we wouldn’t change anything for an engagement and first names is my preference. I’d feel weird if she started calling us Mom and Dad. My mother called her in-laws Mother B and Father B. It always seemed kind of formal to me. I called my in-laws by their first names.
I’d definitely make dinner celebratory - have a nice toast. I think given that they are now engaged it’s okay to ask them how long they are planning to be engaged.
Hope you are celebrating now. I just saw this thread. I would get a bottle of champagne to celebrate.
D1 is living with her BF of 5 years. They plan on getting engaged next year because he needs to save up for a ring. The BF started calling me Mrs. X, then he worked at the same company as me, so he called me Oldfort at work. Now they are living together, he calls me Mama Oldfort. I think that’s what he will be calling me going forward. I do not like my kids’ friends calling me by my first name.
Forgot to add - Congratulations.
Re: “Mama Oldfort”
This is a creative way. For the “Oldfort” part in “Mama Oldfort”, does he use your first name or your last time?
For my grandparent’s generation (maybe my parent’s generation too, but not universally), the husband and the wife did not call each other’s name. Definitely not honey - LOL. Kind of calling each other “your dad” or “your mom”. Pretty weird.
Mcat, let’s not get too technical! Lol
As long as my future DIL will not call us “mama bear” and “papa bear” literally, we will be fine with it.
How about “we are looking forward to having you join our family”…since that hasn’t happened yet.
@mcat2 - my first name. D2’s BF is still on Mrs. last name.
@oldfort, Thanks for your clarification. It is rare that you have the opportunity of working with your D’s BF/future SIL in the same company. You must have “evaluated” him up close. LOL.
Not sure if anybody has mentioned this: Since OP’s D may follow her BF/fiancé to another country, there could be some “work visa” legal matters (and the fiancé of a work visa holder) to sort out.
Becoming fiancé or even getting married may or may not help with the process (if they need to move overseas within a short time, and the new work location is not a part of the US.)
Visiting some country for a short time could be very different from staying there for a long time, unless you are citizens of both countries. For the former (I.e., just visiting), if that country has the visa waiver program agreement with the US, you may not even need to obtain the visa. Even if you are eligible to get the proper visa for extended stay, this process could take time. The government everywhere is not that efficient, generally speaking.
For the Australian-Korean couple example that I mentioned recently, they said that, after their marriage, it took them more than 9 months before this couple could travel to Australia. This is a case that getting married may not be the fast way to enable them to go to another country. The fastest way? Spend your money potentially frivolously to become a foreign student. (Why do so many countries welcome foreign students?! Cash cows for them?)
We have friends whose D married a British citizen in HI. They had a LOT of paperwork, cost, and time to get him legally able to remain in HI and then had to jump through a lot of hoops so they could legally visit the UK and his family and friends. It’s good to check into these issues so there are fewer surprisies. One needs a GOOD immigration attorney, versed in the intricacies of the law as it changes.
There was. O hoops for me to jump through, perhaps because my husband was working for a UK company, he was a technical founder with founder shares, the company sponsored him for green card. I never had any problem visiting UK legally. I doubt that would be a problem even if he was not a green card holder.
For the benefit of other future in-laws reading this thread I wanted to share my story. My inlaws never addressed the name issue. I never mentioned it because I thought it was their prerogative so I continued to call them Mr. and Mrs. last name. Later, I wondered if they thought the name should be my choice but at this point it went on so long that discussing it felt awkward. Finally, after five years of marriage, we had children and I started calling my inlaws by their Grandparent name.
My inlaws are formal and traditional but we are not talking Downton Abbey There has never been any animosity between us but the whole situation was very awkward for me. Unfortunately, their continued acceptance of the Mr and Mrs moniker made me feel that I was not truly a part of the family.
So, if you want your children’s SO to call you a particular name, please discuss it with them.
We had a good dinner. I am glad I gave the matter some thought, the way she told me the news, so matter of fact and low key, I wasn’t sure if she was happy about it. If she was not coming our way to pick up some stuff from our house, we won’t even see them till sometime late Nov. Anyway,she looked happy, well both of them look pretty happy. I am happy to hear the ring took almost a year to design and make so a lot of thought must have gotten into it. Apparently the fiance designed it with input from my d. I really liked that.
I greeted them at the door and when addressed asked to be addressed by our first names. The fiance didn’t change, and I repeated it once. If he chose to continue to address us as Mr and Mrs it is fine with us.
I told them we will have a proper celebration when we can all get together in mid Nov and have some champagne.
We asked what are their future plans and they both said it’s now up to my d to plan. 
Now I feel I can finally clean up the d’s room and change it into my office, which I need badly. :D/
I am not big on the form of a celebration of marriage, I said to the d I don’t have much opinion on how they want to do their wedding. Their dad told me if they need financial help we will provide it.
I said to my d I would prefer before stepping into marriage I would want them to spend some effort and time to go for pre marriage counseling. I think all couples need tools and skillsets for a successful long term relationship. Sometimes love is not enough as we all know.
My in laws never addressed the name issue either - I went almost 30 years of marriage (before they both passed) not really calling them anything - just talking to them! I may have called my FIL his first name a couple of times when I really needed to get his attention. It always bugged me not to know what to call them. I talked to my H about it and he always just shrugged his shoulders. He did call my mom “mom” - I think he just felt comfortable to do that.
An engagement is supposed (at least traditionally) to be a planning period between where the couple decides to get married and when the actual wedding happens, so that the wedding can be planned. Some people don’t use it like that, but traditionally that’s what it is.
Probably depends on how big the families are. The fewer the people, the easier it is to just do the city hall thing. My parents just did the city hall marriage and had dinner with my mom’s dad and brother. Though if all the parents are living I’d have to imagine that the wedding route is normal.
After 24 years of marriage, I still address my inlaws as Mr and Mrs. I would never call someone else mom or dad, it doesn’t feel right to me. A lot of it seems to be cultural. We live in a predominately white area, and I constantly have to tell my kids friends to address me as mrs. partyof5. Black parents are notorious for not letting you address them by their first name.
^^^ This Hispanic mom, too. I’ll never forget the first time an 8yo called me by my first name. Wooooow.
Partyof5-that’s interesting. What H’s (black) family does is everyone is on a first-name basis-aunts, uncles, in-laws. H’'s parents are deceased, so I don’t know what they’d have preferred, but for the young married couples, they all use first names with their in-laws. The little kids seem to be divided on calling us either by first name or aunt/uncle. HOWEVER, D’s friends from church or school tend to call me Miss Firstname and H Mr. Firstname, as do the kids working in the grocery stores I shop at.
@sseamom yes, if someone is related to you, it is okay for first name basis, but not for a non relative that is not your peer. And yes, if you are a kid, it is common to call adults mr. “andy” or miss “tracy”.