My advice is don’t believe anything he says until you see legal paperwork from his attorney. He can (and probably will) say anything to you that he thinks may scare you or worry you. Sherriff’s deputy or not, he still has to go through the legal system too. I don’t believe his lawyer can send you anything personally if you already have a lawyer. His lawyer, I BELIEVE, has to send anything legal to YOUR lawyer. As long as you have a retained lawyer and haven’t formally dismissed them, then any legal actions go through them—then your lawyer forwards to you.
Now as far as the adultry thing goes. If you haven’t done it, don’t worry. He would have to have evidence to that affect. If he has emails, then I suggest you do not email that person any more…especially if the emails show that this person may be advising you to leave.
I don’t think he has a case for Divorce from Bed & Board. I don’t know what ‘litigation’ he is talking about, but there may be something his lawyer can do. BUT you have a lawyer too. Make sure he/she is a good one and tell your husband to send whatever paperwork to your lawyer.
From what I understand, he can’t kick you out without just cause. Don’t be intimidated by him, and don’t worry until you have reason (ie: you get a call from your lawyer and he says ‘I need to see you’). Even then, don’t worry. Let your lawyer do his job. You just protect yourself.