You bring up 3 issues in your question, 1) is there a cooling off period, 2) does it matter that only 1 member of the marital community signed the lease, 3) what is the requisite condition that you must maintain the premise.
1) Is there a cooling off period - Unfortunately no, a lease is like a contract and it is going to be valid when it is signed so long as it meets the definitions of a valid residential leasing contract.
2) What if only you signed the lease - In Washington, it only takes one member of the marital community to bind the couple to a contract.
3) What level of care must the property remain - Unless it is clearly stated in the contract that the property must be maintained at "showroom" conditions at all times, I would think that normal maintenance of the property should suffice. Under Washington law, a landlord may not charge you for damages to the property that are simply a result of normal wear and tear. In essence, requiring one to maintain the property at a showroom condition would be making the tenant pay for the upkeep of the property beyond the normal wear and tear provision.