A party can only be held responsible for repayment of a debt if they signed the original contract, loan agreement or credit card application. If your spouse or partner did not sign the original contract or requested a credit card, they cannot be held responsible for the debt. In Canada, marriage alone does not make you responsible for your spouse's debts.
Regarding credit cards there are two ways in which the second party can be held responsible for repayment of the debt. One is where the individual actually requests a secondary card and signs an agreement saying they accept full responsibility for current and future debt. The other is where the credit card company sends a card out in the second individual's name with the primary cardholder's number and the second individual actually signs and uses the card. Use of the card will hold the secondary person responsible for any past and or future debt. If you want to remove your spouse or partner from your credit card or loan document, you must get confirmation in writing from the financial institution. Without written confirmation there is no guarantee the institution has removed the second party from their records.
Also, responsibility for debt between spouses as listed in a separation or divorce agreement does not legally bind a financial institution or creditor. Unless you obtain concurrence to the division and re-assigning of responsibility of debt from the creditor, they have the right to pursure anyone who signed on the debt.