So I received a STD via email from an acquaintance. We're not super close now, but we were closer a few years ago (now we live across the country from each other). The STD was addressed to "Ms. Mbross3 and guest". She contacted me asking for my new address for the formal invitation. I sent her my new address along with BF's name (we live together now, but this acquaintance has never met him). I just received the invitation in the mail today and it was addressed simply "Ms. Mbross3" no mention of BF or "guest" or anything.
Now this wedding is across the country from where we live now, and I wasn't sure about attending, but BF and I thought it might be a good opportunity for me to see some old friends and for us to maybe take a few days off of work (for him) and law school (for me) to take a mini vacation in a different part of the country. Of course, if he's not invited that kind of changes our plans and I would probably RSVP "no".
I know that BF isn't really a +1 since I'm not single, we live together and are a social unit, I just wasn't sure how to phrase it. Is it rude to ask if he's invited? I know etiquette-wise only the people addressed on the invitation are invited. I'm just confused since the STD said "and guest" and I specifically sent his name and a little chatty email about how we live together...
Thanks ladies! 
----Update----
Thanks for all the advice ladies! I called to chat with her, we spent some time catching up and then I casually asked about BF being invited. She said that she had chatted with one of my BFFs (who is also invited and from the same area as I am) and that BFF's BF wouldn't be able to make it so she thought that BFF and I could travel together and so she eliminated my BF and also another friend's BF from the list. She said she had plans to call all three of us in the next few days and suggest we three travel together, get a hotel room together and make it a "girls weekend". She said something about how this would be "more fun" for all of us. At that point I just bean-dipped and got off the phone. I called BFF and this other girl (who we are also good friends with) both were pretty surprised that this was planned (the other girl was actually planning to call and ask if her BF is invited--but now she knows!). Anyway, none of us will be attending. I guess we'll save on our vacation time!