Roger that. After my separation and then divorce, I continued to participate in a special interest forum - and the in-person get-togethers - as my EH. It's gotten easier over the years - we try very hard to maintain an amicable divorce b/c our child, but at first, those get-togethers were uncomfortable for both of us.
I had to resolve not to address ANY personal issues during these events, and to act politely (you know, Dr. Laura's advice), as I would with anybody else.