I didn't read the other responses yet.
But for me, well you are NOT wrong about this.
I would feel the same way.
EACH Mom/parent, should choose what is best for THEIR child/family. Not just have it chosen for them.... and certainly not without asking you/the Parent about it FIRST.
You should do what is best for you/your child/and instincts.
I too, feel that when on a a trip, you can't just leave the kids... ALL day, to do "adult" things... for me and my Hubby, we always INCORPORATE the kids and do what is family oriented... skipping those we feel is not inclusive for the kids. AND you are pregnant... um, yah, so for them to assume you will attend an ALL day wine-tasting event/dinners... is not real considerate. AND being pregnant and being on your feet all day... will be tiring not to mention dehydrating, which is not good while pregnant.
They should have asked you first.
What does your Husband think?
And certainly, being pregnant, you should not be left alone, to manage your other child, by yourself, while the "adults" are out and about on all-day event/dinners/outings.
Do what is best for you, your pregnant status, and your child.
All the best,
Susan