Season of the Cats by Sargent, Pamela;

Long description:

Gena and Don seemed an ideal couple. Young. In love. Playful and imaginative. They often pretended to be cats, purring and playing and taking on pretend roles in their made-up cat-world of "Cat"alonia! When they move into their first house and money becomes tight, management of household finances -- what the shared Household account pays for versus what share goes to personal expenses -- becomes a contention point. And their imaginary world takes a darker turn, with Household becoming an evil that threatens the harmony of their beloved Catalonia. But Catalonia and its feline residents have become so real that they begin to intrude into Gena and Don's world, appearing as stray cats -- with a mission of their own. And they aren't going to let the young couple destroy their world, at any cost! Season of the Cats is a delightfully contemporary fantasy by the award-winning author of Eearthseed, the Venus Trilogy, and The Alien Upstairs.