How about a personalized guitar pick? You can have it engraved with his name, initials or even a special message. You could also get him a personalized guitar strap or a book on how to play a new instrument. If he has mentioned an interest in a specific instrument, you could also consider getting him a lesson or two with a local music teacher or an online course for that instrument.
Or you can get him a star map with the date of your anniversary.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.