Agreed do not write that letter, do not get her a card, do not even bring it up on the day of unless she does and even then be "as if" as possible.
There will be time for closure, on the day of your anniversary is not it and you may tell yourself its not trying to win her back or its for you just as much as it is for her but that is just not true.
Stay strong work on you, it's hard, one of the hardest things you will ever do because it's counter intuitive to what everything your body and mind is telling you to do but trust me brother it works and it's what you need to do
