I wouldn't go with her to the reunion. I would tell her "W, I am not interested in pretending to be a happily married couple just for the sake of appearances." Then politely thank her for the invite and do something else that night.
I would't but I'm getting some serious BBQ (trust me - where I live there's some BBQ!!!) and beer. I will know a couple of guys there as well. It is only for 3 hours, then I plan on going and doing my own thing after.
M 06/08 D10, D8 1st S 05/10 I move out Move back 07/10 same bed then me in guest room 2nd S 09/10 W out one week W back 09/10 W in guest room D-bomb 10/10 S - living together No D yet filed