Hi Superfine!
If you havent been for about a year and your wife has stopped going also, it sounds as though the final step is more in your mind that in any action you have to take. It sounds to me like you have done an effective fade.
I suppose if you wanted closure you could go back for one final meeting. After a year away you would probably be surprised at how mad virtually every sentence made you, and it would confirm that you couldnt stomach it anymore.
Or were you wanting to make a more formal break? By sending them a Disassociation letter for instance? I found a good long fade was enough for me.