Good question. Assuming that you application for the green card was based on your marriage to your U.S. your initial green card, if approved, will be conditional. Under the Marriage Fraud Act, all green cards issued based on marriage to a U.S. citizen are conditional for two years. Prior to the expiration of your conditional green card (assuming it is granted) you would have to file a petition to remove the conditions on your residency. With a few exceptions this petition must be filed jointly and therefore if you are no longer married you could encounter problems and be unable to obtain a permanent green card. This isn't anything to take lightly and I would encourage you to consult with a qualified immigration attorney to discuss the possible effects a divorce may have on your legal status. I have included a link to an article I wrote about this that provides some more information. I hope this helps. Feel free to email me with additional questions.
If you are not married or are legally separated at the time of the adjustment of status interview, you will not receive the approval. You will not become a permanent resident and thus, you could be subject to deportation proceedings.
You should consult with an immigration attorney immediately.
Your question depends on serveral factors and timing is crucial. It will depend on if you have had your permanent residence interview. You need to seek the counsel of an immigration lawyer.
From what you described you have not yet been called in for an interview. I suggest that you make an appointment to speak with an immigration attorney in the near future. The paperwork you have filed is based upon a good faith ongoing marriage. You will need to evaluate what your options are in event of a divorce.
You are a conditional permanent resident or you may not have this status yet if you haven't been interviewed. Once a couple is married for over two years the CIS ( immigration service) must grant a permanent green card if the marriage is determined to be a viable one. Every area has a processing guideline that can be found on line as to the usual amount of time to adjudicate. Six months is very short but if you properly filed you should have received a work authority by now.
If you have not been interviewed, I suggest you see a lawyer immediately as you would be denied if you and your husband do not interview well or if you are separated or if you have poor documentation. This would mean that you would be put into removal proceedings to appear before a Judge. Unfortunately, you would then not be able to proceed on the marriage by getting a divorce as you must have an I-130 approved by CIS for the Judge to have jurisdiction so this means you would need another avenue of relief.
I suggest you talke to an attorney who is experienced in this area without delay.