Separated 6 yrs. Husb lives in house and has been paying on a modification for 5 yrs. Papers received for new terms. I don't want to sign.

This is complicated and depends on many factors. Do you still have equity in the house? Do you earn more money than he does and would you be paying him spousal support in a divorce? Who's been paying the mortgage and taxes since you left? Ideally you should get your name off the deed and loan and if he wants to stay in the house he should find a new co-signer for the modification. But if you have equity you need to be compensated for your share. Much more information is needed in order to answer your questions.