Sunday would have been my 12th wedding anniversary. I sometimes can't believe it's not going to be, like I'm unsure about how that even happened. Anyway, life seems better than a few years ago in some aspects, even with all the pain and work of transitioning to a bit of a new life. But some of these days still carry a punch in the gut.
There will always be days like that...so focus on the better days, make them even better, and seek to let go of the past, over which you have no control.
Not sure if this helps... But almost everyone has those dates on the calendar that are hard to remember. I have never been married, but I've had losses of family, so birthdays, date of deaths, dates (or approximate dates) of important events can be difficult. The worst example, though, is a cousin whose stepfather died on her birthday. Every year when her birthday rolls around, I think of what an incredibly difficult day it must be for her.