Often when someone buys a new book, the first things they do is throw away the dust jacket or wrapper. Certainly libraries do. This might also help to conceal the subject matter of the book, should your spouse object to particular genres of literature.
One French collector removed but saved the illustrated wrappers and advertising copy from his book collection. Eventually, the wrappers were bound together and are now in the collection of graphic arts. Authors include Guy de Maupassant, Alphonse Daudet, Armand Silvestre, Catulle Mendes, Jules Hoche, Emile Driant, and many others.
A collection of over 200 French illustrated wrappers and publisher’s specimens (Paris, 1882-1907). Graphic Arts 2011- in process.