You have a choice here. The first option is writing and submitting a lease agreement that outlines you shall be leasing the dam from your spouse and includes both your signatures.
However, since the owner of the dam is your spouse, you do have a second option. You may simply put both your names on the litter listing form as the official breeder. Please note that your spouse’s name must be added to your club membership and you must send in a joint ESC BR&R form if you choose to list as married co-breeders.