Among the many things that no one tells you when your spouse is alive and well is that one day, your anniversary will change. What was once "our anniversary" will be just another day of pain, one that's been overshadowed by The Deathiversary--the happiest day of your life displaced by the worst day.
There were plenty of people at my wedding who aren't here any longer. My grandfather, my great-grandmother, my grandmother, an aunt, an uncle, an bunch of my grandparents' friends I'd known my whole life--they all lie buried now, no longer here to witness the world still turning without them. And so does the groom.
But. I've come through two Christmases, four birthdays (two of his and two of mine), a bunch of other holidays, one deathiversary, and one anniversary already still standing--or at least, having gotten back up after being knocked to the ground. I can do another day.