The IRS allows leeway when one partner in a marriage prepares joint tax returns that the other spouse signs without knowing what is actually in the return. The innocent spouse rule provides that a spouse who unknowingly signs a fraudulent tax return may be excused from tax liability for penalties based on that return. It is difficult to prove that you are an innocent spouse. Review IRS Publication 971 available at www.irs.gov which has information about the innocent spouse rule. Also, talk to a tax expert. For the details on the ins and outs of taxes and divorce, review IRS Publication 504 available at www.irs.gov or by calling 1-800-829-3676.