1. Budget for books the way you do for food and electricity...or you won't have food and electricity.
2. Read each other's books.
3. Keep separate accounts at the used bookstore.
4. Books are paper. Paper is good insulation. Line the walls of your house with bookcases. Fill them. It's the environmentally responsible thing to do.
5. Read aloud to each other.
6. Keep stray dishes, flowerpots, etc... handy to throw during arguments, lest you be tempted to throw books.
7. Respect each other's differing literary tastes.
8. To communicate with a spouse who is reading a book, replace his or her bookmark with a note.
9. James Fenimore Cooper is your friend.
10. Work out a shelving system together to ensure both of you can find the books you need when you need them.
11. For the sake of your financial stability, do not often shop for books together.
12. A bookless parlor is a howling wilderness.
13. Buy only one copy of books you both love. The thought of having to buy replacement copies is an excellent divorce deterrent.