who signed the lease?

whomever signed the lease is responsible for the money. If you didn't sign, then you don't have to care. If you were the only signer, then you have to pay the whole amount. If both signed, then 50% for you. Also, exactly what is the statement in the contract that said you have to give 60 day notice? Contracts are serious, you can't just decide to ignore it on your own.