Am I obligated to pay my spouse's debts?

The law in New York State seems to be that, as a general rule, each spouse is responsible for his or her individual debts and both spouses are jointly and severally liable to joint debts. In other words, just because you are married does not necessarily mean you are automatically responsible for your spouse’s individual debts. It depends on the situation, how the debt was incurred, what was the express or implied relationship of the spouse to the debt. Was the intent of the parties of the marriage to have an “agency” relationship with respect to the debt? If that is so, and the debt was really a “family debt” paid for with family funds, the parties were living together at the time the debt was incurred, both spouses were paying on the debt, both spouses knew about the debt and led the debtor to believe it was a joint debt (even if it may not have been a joint debt.)
Did that make sense? You are responsible for your spouse’s debt only if it was a joint debt and that joint debtedness can be either express or implied. So if you and your spouse were living apart but not legally separated for 5 years or so, and a debt is incurred, and your spouse is the one who has been paying for the debt, it’s unlikely that you will be held jointly liable for the debt. Conversely, if you have been living together, and both you and your spouse paid for the debt on a joint account, for instance, then you could probably be held liable for the debt. A creditor could legally come after you for the debt and even if a bankrupty were to result, the matrimonial court would lack jurisdiction to stop your creditors from moving against you in a bankrupcty scenario.
So the question again is, what is the nature of the debt? How was it incurred? Who has been paying for it? What is the state of the marriage at the time the debt was incurred? What are the express and implied promises to pay that were made?