Don’t confuse the label “innocent spouse” with “injured spouse”.  The two are very different.  Innocent spouse refers to the possible relief for one spouse from joint and individual tax liability on a jointly filed return.  On the other hand, a spouse may become an injured spouse when he/she marries someone owing a debt for taxes, child support, student loans, etc., incurred prior to the marriage.  The injured spouse rules are covered in Chapter 10.4.