I personally think that anniversaries apply to the same rule as not saying "I love you". It is a painful reminder of the day that spouse made a solemn promise to you and to God that they would never leave you, stay with you for better or worse.
Oops!
And, seriously, she has put in paperwork to end your marriage, why celebrate it? If she says something to you about not mentioning it, I would kindly point out that SHE is ending the marriage that you consecrated and made vows to each other, so why celebrate something that is now null and void?
