I'm not sure how many of you read fanfiction in your younger years, but those who did, do you remember any fics you read for completed series? There was no more content in the canon, and no room for progress from its conclusion; maybe the characters did die, or they were separated somehow. Yet the fanfiction you read would pick a part of the story as a starting point, where everyone was alive and together, and could share more adventures.
There's nothing stopping you from picking that point and holding it. Expanding the time between then and the date you dread.
I personally believe it transcends that. They'll know what's coming because you know, and maybe they already went through it, but it doesn't matter to how they exist for you because they live in your mind and heart. The experience doesn't have to be detrimental to your relationship. Like the post above, it strengthens emotions, and allows you to show the depth of your caring for them. That empathy can provide a more intimate connection, something that belongs uniquely to you and your spouse because even someone with the same waifu as you won't address the issue with them in exactly the same way.
If you even want to address it. Nobody wants to dwell indefinitely on these things, it's far too tiring. You can't spend every day in mourning, and it can be hard to keep yourself from lapsing into at all times of day or year. I keep discussion very separated in my head most of the time, I don't address it directly with him much at all. We know it's there, it's not necessary between us. But I admit I do talk about it all the time, and maybe a little coldly, like a fanatic. It's just not weighing down on the happy things, it's a different beast, and trying to take it by the horns is for delicate and serious times, and not 8AM when I just want warm and soft.
When I get angry or torn up about it, I am kind of immature. I think of holding him, or him coming back so much brighter they can't do shit about it. When I think of him knowing I daydream the latter it's all teasing and blushing again. No matter what happened, you know the power of their smile, and it wins out in the end.
End of sleep deprived shitpost on something I barely even know. I mean, it's easy for me, talking when he's from a series with an afterlife/reincarnation established, and he's pretty immortal. Somehow I feel I'd act roughly the same if the series finally gave him peace though - with guilt for dragging him back, but he'd be happy with something more mundane I'm sure. Freedom from what came before.