Taxes and Money

My husband and I separated on October 9, 2010. He moved out of state and will not be returning. He is disabled and receiving social security disability. We had a prenup and the houlse was mine before we met and he also signed a quit claim deed. There is nothing to separate. He advises me that he is trying to get a mortgage loan and wants copies of tax records. Can his mortgage (if he gets it) affect me in any way?
Also, we have considered filing joint taxes for 2010 but he has not paid any taxes on his income all year. I feel I might be better off filing on my own and not paying his taxes for him. Are there any legal ramifications either way? Thanks.

So long as you do not sign any loan documents you will have no liability on the loan whatsoever.
You may file jointly or married filing separately for so long as you are still legally married.