How about an ice sculpting tool kit? There are many ice sculpting tool kits available that include a variety of different chisels and tools to help create intricate designs. You could also consider finding a local ice sculpting class or workshop for the newlyweds to attend together as a unique and memorable experience. Another idea is to commission an ice sculpture to be made specifically for the couple's wedding or to have their initials carved into an ice block for them to display at their home.
Or you can get her/him a star map with the date of the wedding.
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.