The lawyer wants your financial information because once you got married, your assets (and debts) got legally combined to some degree. Her creditors may now seek repayment from your assets as well, since the bankruptcy is occurring while you are married. It would have been better to time the marriage to AFTER the bankruptcy was final -- then your marital assets would not have been affected.
You can obviously fight this in court, and may succeed, because the debts were incurred by her, prior to the marriage. But if they go after your assets and you have to deal with it in court, it counts as affecting you, doesn't it? Creditors will go after everything they can, in the hopes of maximizing repayment, and the courts will rule on actual assignment of debt.
Her bankruptcy will affect her individual credit rating. You may be able to take steps to ensure that it doesn't affect yours as well.
CAVEAT: I am not a lawyer, and this is definitely an area where you need competent legal advice. You may want to discuss the situation with a lawyer (she's already got one, so I'd start there) to see ways to minimize the impact on your overall assets.
EDIT: Sorry, I was answering the questions 1) Why is my information needed, and 2) will I be affected? It's reasonable to assume the asker also needs to know what to do about because he is affected. I agree the online websites may be useful to stay informed, but the best approach is to talk to a lawyer and get competent legal advice about your specific situation. Usually people go to the web to avoid paying for a lawyer, but in this case, the lawyer is already engaged. My advice remains -- talk to the lawyer to find ways to minimize the impact of the bankruptcy filing. It's better than trusting non-specific bankruptcy advice on a website (no matter how well written.)
You mean like Feinsteins husband? Oh wait, he is an investment banker. Hmmm, good question.