"Of course I know what you wore on our third date and what you ordered. How couldn't I? It's important! Am I not as important to you as you are to me?"
Only after spending time and putting in the work with a partner who had their own memory issues did I actually bring this up to them and a therapist. I recall a conversation where I told them it was OK that they had forgotten what we ate on our first date or what I was wearing, because I didn't want to be resentful over unimportant things. The therapist asked me if I remembered most of our dates - where we went, what we wore, what we ordered, movies or shows we saw, etc. I remember being confused - of course I did! Who wouldn't?
My therapist explained that this was really uncommon, especially in the scale of years and decades. I had never considered it before that. It changed how I interacted with the world and I wish I had known sooner.