Etiquette Snob here (comes with my career)
Ok here is how this is strictly from the most formal point of view.
Lol… it is more of a breach of Etiquette that your FMIL is the HOSTING the Shower (a direct family member)… than it is the fact of WHO she decided to Invite.
BUT in reality… you are BOTH totally off the hook for this faux pas
Your FMIL has purposely organized this Shower to be “Meet the Bride & Groom” by her inviting family friends, neighbours and the such (obviously she LOVES you guys a lot, and is very proud of the union… and that is something MANY Brides here in WBee would kill for)
So relax… and go along for the ride.
Be sweet, be gracious… and smile a lot (till your cheeks hurt)… and don’t forget to write those Thank You Notes filled with marvellous kind words of how great it was to meet everyone… and that you “treasure” the gifts they’ve given you
Now, if you do choose to hold / Host an After The Wedding BBQ that would be a nice gesture. Not required, but a nice thing to do. I am sure your MIL would be pleased to help… and proud to show off her AMAZING Daughter-In-Law once again.
Hope this helps,
PS… Double check with your MIL… make sure she hasn’t bent any other Etiquette Rules… you don’t want to find out that somehow this is a Money Shower etc, or a collection of cash to buy a group gift. On the other hand a good old fashioned Theme Shower would be ideal… just let her know what it is you guys would like are in need of (Bedroom Linens – Bathroom – Kitchen – Cookbooks – Wine – Garden Tools – whatever fits you and your Hubby’s interests)
# 1 – As a Meet & Greet this really should be an occasion when it is more like a Couple’s Shower… so BOTH you and your Hubby-2B should be there. Hopefully your MIL has set it up that way (Guests would be not just all Ladies either). IF she hasn’t however, it isn’t a big deal… just go with the flow and be the out-going “Future Daughter-in-Law”… (maybe your Hubby-2B can drop by early to say Hi to everyone too)
# 2 – Meet & Greet Showers… with Neighbours etc. AND Church Lady Showers, or those organized by one’s Work Colleagues, OR one’s social group (ie you are a Brownie Leader, and the other Leaders throw you a Shower) ARE not a situation where there is normally no expectation of the Attendees getting a Wedding Invite. They are meant to either Introduce the Bride & Groom as a couple (or the Bride to the family)… or just out of LOVE for the person who is about to be married / have a baby etc.