Start by reading all the articles on the main site about dealing with infidelity. They contain invaluable information about what steps you need to be taking, and what to expect. That base of understanding will make it easier to implement the step-by-step advice you'll get here.
First, take a deep breath and relax. Time is your friend. You have a very good chance of winning through this with a recovered M, and you yourself will recover well regardless. Just use a few days to read and learn. Your upcoming efforts will be better for it.
Second, you need to expose. Since the A is allegedly over (though I have my doubts), your main targets need to be family (hers, too, if you know who she is, and if you don't, find out asap), close friends, and your WH's superior.
Personally, I would snoop very vigorously for a few days before exposing to the family/friends group, as your note will look a little different if you find out the A is still going on.
I would also talk to WH's superior immediately, today. The military very much frowns on adultery, and you have tools available to you that the ordinary BS can only dream of. If you're in a small town, you will NOT EVER be able to recover while OW is still around, constantly threatening your M with her presence. Your WH will never become a FWH while he is constantly hearing of her and being triggered, and never knowing when she might waltz into his office to say hi.
Your WH needs to be transferred right away, yesterday if possible.

All your efforts to R will be so much smoother having the two waywards separated.
As to the rest of what he's said and done, don't stress it too much. As you read on here, you'll find out that he's reading straight off the Wayward Script.
Keep posting. We'll help you through this.