A wedding anniversary is the celebration (and achievement!) of love, trust, tenacity, tolerance, partnership, and commitment. It marks a milestone, as well as a symbolic gesture. It defies the limits of anything before it, it's paramount and testament to you as a couple. Namaste and I wish you Anand, a state of sublime bliss.
ETA: For clarification, I didn't want the key. It's just heart warming to see stuff such as this.
ETA 2: I did not realize I had necro'ed this thread - I'm sorry