Credit Card Obligations

I am in Texas.

My question is similar to "Missy's" in that my boyfriend and I had a joint credit card and when we broke up, I called the credit card company and asked to have my name taken off. They told me that since they had extended credit based on our combined income, they would not take my name off, in other words, I am still liable for his debt on the card.

My question - I have not charged nor signed any of the current charges on the account which amount to $9000. How can I get my name taken off the card? They suggest I have to get a "legal separation" which I understand is not an option in Texas. They also suggested I get him to sign a letter saying I'm not liable for his charges - he won't do that!

Since I didn't charge any of the current balance (and they will not find my signature on any charge slips), how can I terminate my responsibilities on this account? He can drag me along on this account forever and stop paying and they will come after me for collection even though I've tried to get off the account.

Thank you.

Linda