If you do not want the divorce, then don't sign the papers. Fight it, drag it out as long as possible and keep trying to talk with your H about reconciling. BUT if he has filed for divorce, you must answer legally or you could really get the shaft. You could ask for court ordered marriage counseling. I was served papers a few months ago, and I responded legally with my own lawyer, and then within two weeks my H figured out he was making a mistake and we have worked everything out! Our problems were different from yours, but people make it through affairs all the time. (With the help of Dr. Harley's his Needs Her Needs program, my H and I have made huge progress in our relationship!)
Even if you don't want the divorce, you MUST look out for yourself.You need good legal advice. He may at a certain point (depending on your state's laws) be able to take the papers to the court and proceed without you, and have the divorce granted anyway, so you may as well stall as long as you can. Let him know the divorce will also cost HIM, that you are entitled to things just like he is, no matter WHAT you did! He may rethink it when it hits him in the pocketbook. He is obligated, isn't he, to support you in the interim? Hasn't he been ordered by the court to do so? You have been unemployed and he was the supporter and he cannot just throw you out on the street! No no no! Most courts would really frown on that, even if you did have an affair. He may be ordered to pay your legal fees. Is your state a no fault state? What kind of protective order does he have? Those are hard to get, even with abuse, and are temporary. A restraining order is also temporary, how long is it for? If you DO file, you could get temporary spousal support and use of the home in the interim, and you may be able to work things out with your H and continue to stall.
You SHOULD get legal advice, you MUST know your rights, and is your attorney advising you as such? but you also need to ask yourself why do you want to stay married? You were unhappy enough to have an affair, so is it the marriage you miss or the financial support? (Not judging you, just asking you to be true to yourself.) Is the marriage really what you want?