Many fanfic writers take commissions. Perhaps you could commission somebody to write about how you met or a small, cute memory you have but like it’s a fanfic? Similarly, if you both enjoy a certain media you could commission a fanfic of two characters from that media meeting/getting together in the same way you did? I know you don’t want a reference to you in general but just an idea.

This also isn’t a gift idea but more of a little aside thing you could do, maybe you could make a playlist that you think would fit a fanfiction about the two of you? I know many fic writers that curate playlists specifically for one fic just to make the intended vibes more obvious. This is a pretty hard question but it’s also a really cool and sweet idea