I think, since your wife IS -- albeit conflicted -- currently slated to go to Retro with you and to work on the marriage, it would be entirely appropriate to celebrate your anniversary. I just wouldn't do anything over-the-top, and I would NOT expect anything romantic, as you'll only set yourself up for possible disappointment.
I think a dinner reservation, perhaps even at "your" restaurant, with a simply-stated card (nothing too mushy or romantic) and nothing in the note that conveys any pressure or expectations ... either NO handwritten note inside, or something that just honors what you said above, would be great.
