I don't believe there is any way your husband could have divorced you without your knowledge. You must have had an attorney for the process, in which case they would know where the divorce was filed. Talk to a court at your local courthouse and ask about this.
How could he divorce you and you not know? The only way I know that to be even feasible is if he lied and filed on "abandonment" and even then he would be required to run an ad in the classifieds stating his divorce intentions. I am speaking for my state.....but feel certain most states are pretty much the same with those regards. When I divorced my ex husband, he was served papers. Even though he refused to sign them, I was still granted the divorce after a waiting period. I agree with dunczn. Is your "husband" telling you that he divorced you? If he truly did, he would have no problem producing the documents. If he refused to show them, I would really be skeptical. Contact the court house. If you call the office that issues a marriage license they probably can direct you.
He could be seeking advice but not actually proceeding with filing the papers... Yet. My husband talked a lot about divorce but it was just that, all talk. Until we went to see a mediator who actually DID file our papers with the court. You do have to sign the petition for divorce if it is filed. Can't do that behind your back... All in all Divorce sucks!' :(
It can't happen without you, for Divorce both of couples should be in Process, the only way it can happen he got a sign of your agreement paper or something to prove you letting him to Divorce you in your absent out of this way there's no way to do it,