"To the wine, no one else had alcohol or cocktails. We have a pretty reasonable alcohol policy. We're allowed a drink or two, just have to stay under our daily total. Ariel and I didn't want alcohol, we wanted fancy coffee drinks and had planned accordingly, which is why I wasn't financing their wine."
This is where it begins to get more challenging. Were the fancy coffee drinks excluded from the portion that was split as well? It seems like either split the entire bill or pay ones own share. I find the I'll split X parts, but not Y parts a rather awkward middle ground.
The fancy coffees were at a different establishment, so they were never part of the bill in question. From the OP:
Ariel and I had traveled into the conference together, during our travels we'd planned to have dinner and then have fancy coffee/ teas and dessert at a coffee shop at the resort.
The OP and Ariel were saving their money to have coffees and dessert later. Thus, they had a smaller
restaurant bill than they might otherwise have had, because they did not get drinks or dessert at the restaurant.