My sympathy for your loss.

I had similar experience after I lost my Dad.

There was something I did, not not quite so soon, but in years following, when the sense of loss kept finding me and choking me, when I would realize it's his birthday or that it's been a year, or when I was in some place that we've been together, or I drove on a street where funeral parlor was.

So this one time, for an anniversary, made a sort of a private seanse/wake/memorial ceremony. I gathered his slides collection from his travels, and a few of his personal things, his wallet, his glasses. I arranged everything on a table lit a candle and asked his spirit to come and be with me. And then I started watching the pictures imagining how he was taking those pictures, and talking to him about them, and telling him how much I miss him, and how sorry I was that I did not love him well enough before he died. I let myself talk to him as if he was with me in the room, invisible. I let myself cry, and I kept watching the slides, holding his glasses, till late late into the night, until the slow the candle burned out, and I could not cry anymore. It did bring me some peace.