Less so, mcat. Try to stop holding your breath and relax. Your sons relationship,is still young.
I second what LasMa said.
@mcat, please find more you enjoy in YOUR life, so you will have more to do an think of than your S who is very far away and busy with his life. As others have said, it is very early days yet in your S’s relationship with this young woman.
“It surely would mean something VERY significant in OUR generation. I would imagine it also means something significant in the next generation.” It all depends on the people, in the OP’s D’s case, it may not be that serious. Young people today have different expectations then we did, and living together can mean the same thing as being a couple when they don’t live together, and they can do it not expecting it to be long term, depends on the people. Back when I lived together with the person who is now my wife, we were serious, and back then while cohabitating wasn’t unknown, for many people it still was something they wouldn’t/couldn’t do, these days it is a lot more common and is a lot more accepted, so there isn’t that much of stigma if they live together, then go their own way. Very different expectations for many of the folks in the younger generations, so the reasons they do things may be very different then if we had done it.
When I was 23, living together meant starting a long-term committed relationship. In D’s case, it seems to mean a significant relationship, but not necessarily a long-term commitment, which to me, seems typical of this generation. My instinct has been not to reach out, and that seems to be confirmed by most posters. But, I have made sure I make personal contact with past roommates my kids have had. As to emergencies, it’s difficult to make phone contact in this country. I don’t even know DD’s number. He knows who I am, and I know who he is, and we can message each other if needed. I am planning a trip to see her in January and I can make personal contact then.
Sounds like a good plan–hope you have a nice visit in January. My D lived in a house that was 3 bedrooms. She had her own bedroom. There were two other men in the house–each with his own bedroom. There was no romantic attachment among any of them. I know it’s a different situation but in my generation in the 70s and 80s, it was less common to have housemates of a different gender.
Why not ask your D for his contact information should there be an emergency, and only to be used when there is an emergency?
I do agree with this idea to have some emergency contact. I think that includes DD’s in-country number, in case, even if you would have trouble using it from the US. Or an email. Something.
In my family, living with someone still means a lot. It means a trial period before marriage. My kids know where I stand on this matter. D1 just moved in with her BF of 5+ years, with anticipation of getting engaged/married in the near future.
If my kid is moving in with someone, I would want to meet him, maybe over Skype if we couldn’t meet in person. Every family (value) is different, but in my view, if my kid isn’t serious enough to introduce the BF to me why is she moving in with him. If the only reason she is moving in with him is for convenience and he thinks otherwise then I probably would have a discussion with my own daughter.
That being said, I wouldn’t contact the BF without my kid’s permission.
This reminds me of this event in my long past history (4 decades ago maybe):
When the dinosaur still roamed the world, that is, when my wife (then g/f) was still a sophomore in college, my mother thought it was a good idea to go to her class to talk to her, without letting either me or her know about it in advance. Mind you, it was not a friendly talk. It surely embarrased her in front of her classmates, and scared the crap out of her. This was how they met each other for the first time - a surprise. Basically asked a random classmate of hers: Which one is the girl named as blahblah? (This probably should belong to that thread about “dealing with inlaws.”)
^^ Oh my.
I DO have her permission to contact him whenever and however I want and I have met him on Skype (she has been very eager to introduce us), though this is problematic with a language barrier with AV feed. DD tells me he speaks pretty good English in person. I don’t think she is leading him on. It seems he is hoping for a long-term committed relationship but is aware of her “live in the moment” attitude.
As to emergency contact, I still don’t see the advantage of a phone call over something like Facebook Messenger. It is how I contact DD and messages show up on the phone just like a text does AND you can set alerts on your computer as a separate app from Facebook. Plus, no need to be Facebook friends to message someone. In my mind, it’s certainly more practical than a difficult to place phone call to another country. DS, who lives in another city in the US, uses it to contact us over e-mail and often text.
And you want to Facebook from an emergency room? Seriously?
You send a message on a messenger service that is owned by Facebook but can be a separate app. Messages show up on your phone like a text and calls sent and received with a ring tone. It really is much more efficient than phone to another country providing you both have access to data. If I was in the ER, I would. Plus, I can use it with my ipad and computer.
@mcat2 And she married you after that? Wow, she was brave!
OP, you raised her right, and he will be fine. Enjoy your visit in January.
I call my parents to their landline phone all the time ( in another country). Also my sisters although I can send text messages to them as well.
Emergency as in something happened and you cannot reach your D on her phone, even as innocent as her losing her phone or no data access. You would want another person and another way to contact her then.
As for emergency contact info, I registered the drivers of our family with our DMV. In case something happens the police can look up the drivers license number and contact the people listed. That program should exist in several states I would assume.
GTAlum, when we all were younger, didn’t have cells, email or FB and were traveling, we often were incommunicado for periods. That was then. My parental concern is: if there were an emergency, what contact info could I give police or a consulate/embassy? I don’t know if we can count on anyone else to have FB.
When mine was away for nine months, we skyped. But my back-up was the consulate,which ran her program, knew her numbers, email, address, the people she lived with, etc.
Since they will be living together over the holiday season, why not just send them both a holiday card with a kind, welcoming message in it? That would 1) show that you recognize their relationship (always a plus for possible future in-laws); 2) let the BF know that his GF has a mother who is interested in her life; and 3) wish them both well over the holiday season (never a bad idea.)
We may do this to DS’s g/f as well for the Christmas holiday.
We sent her a graduation gift a few months ago mostly for the same reason. We felt our communication had been (how can I put it) too non-existent, as compared to the communications between DS and her family members. (Is it likely that a son tends to not to do this as compared to a daughter?) We do not want her to mistakenly believe we do not care for her (or even worse, not welcome her.)
Or maybe it belongs in that thread about “how much should I insert myself into my child’s relationship with their SO?” 
Cards are much more difficult than phone! But, good idea to send a holiday message through messenger or whatsapp. Fortunately, boyfriend has similar ideas as we do about Christmas with none or minimalist presents.