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IF you cosigned on the loan, you are liable as well as he and the lender can sue either of you. It is easier to sue you only in the same state rather than him in FL. Hopefully, when you left he agreed in writing to assume all liabilities. Tell the lender your ex partner will be brought into any suit since it is not your liability as between you two. If sued, bring your ex into the suit.
This is information only, NOT legal advice. No attorney-client relationship has been created. Consult an attorney in your state for legal advice regarding your issue.