quick update:
i ended going to the dinner party. the ex-gf did show up, much to everyone's surprise. she did not let anyone know she was coming until 10 mins before dinner started. it was extremely awkward. we did not talk to each other. besides a quick nod and hi when we crossed paths, we pretty much were out of each other's way. we all went to a club later on, which she was supposed to go to as well, but she never showed. it's probably a good thing because i had a great time with a girl i met that day, who i'd like to get to know better.
i wonder why she decided to go, but i think that'd just be over-analyzing. i'm happy that these forums gave me the knowledge to not go up to her and speak because many of our mutual friends were encouraging me to talk to her and chase her. she is slowly, but surely coming off that pedestal i put her on. at this point, i think i can confidently say that i can continue doing NC either until she contacts me for reconcilliation or i am fully healed and okay with friendship. that being said, i don't see the point of being friends.
i really do think NC helps. it gets the ex off the pedestal and allows you to the person for who they really were.