your current status depends on what you mentioned in your form 80 or form 1221 and on immi online account while filing for 887.
its bit complicated.i suppose you partner was included in your previous visa application
now you cant say unmarried or other as you havent filed for separation yet.If your partner is not in Australia then you cant add him or cant provide marriage certificate because in that case you will not get grant until you husband is in Australia.the best thing can be to provide your marriage certificate to the CO if your husband is also in Australia.This way you will get early grant.else CO can suggest you further.but remember one thing.The more you tell immi the more they will go in deep and will ask you more and that will delay your the grant.
Moreover if you dont not show your marriage certificate then you need to fill form 1022(change in circumstances) but in that case also you need separation document.
only option is ask IMMI randomly on 131881 first.Last option is advise your CO.