I wonder what JA has in mind here-- it could be taken literally (he went broke and she left), or euphemistically. For all we know Mr. Clay might have jumped ship in the West Indies and abandoned her (could we blame him?) --Although if that were the case, Mrs. Clay presumably would not be so ready to defend sailors.

Mrs. Clay's reference is another shade on her character, JA lets us feel how inappropriate Mrs. Clay is. Perhaps she is telling us how Mrs. Clay might be willing to "sell herself" to the right party.