Cyzgy, it may not seem like it, but these 10 days are are blessing for you, given your situation. This is time that he is NOT there, that you can think about exactly what you want, write it down, and practice saying it until it's second nature. Its time that you can use to get your ducks in a row, as it were.
Of first priority is to take care of your health. Eat, get as much rest as you can, stay hydrated. You would think that is self-evident, but when you're hit with a body/soul slam like this, you can easily forget to do all of the above. Next, look up at the left corner for the yellow box and click on The Healing Library. Start reading. Lots of very good information for you. In this forum, any post that has a bulls-eye next to it is also great info. Read those posts. Keep digging up evidence. Make two copies and put on in a safe place that he can never get to.
By the time he comes back, I hope sincerely that you've seen a lawyer and found out, exactly, what your rights are for CS, SS, and property. Move all of his belongings out of your bedroom and put a lock on it. Have it sitting in hefty bags in either a spare room or the middle of the garage. Me, frankly, I'd have the divorce papers in my hand. The minute he walked in the door, it would be war. Slap the papers in his hand. Tell him that you have evidence of the affair with (APs Name). Tell him that his stuff is already packed and ready to go. Tell him that his military career is about to be ruined as you have an appointment with the base JAG in two days (bluff or not, your choice). Tell him that he has one and only one chance, right this very moment, to come clean, make his decision if he is in this marriage 100% or not. If yes, then he and you write a NC (no contact) letter/email or make a phone call to the AP telling her that the affair is over, WH is committing 100% to the marriage, and that the AP is never to contact him again. If no, then he is to remove himself from the house immediately and get ready for an immediate divorce after you see the JAG to out him to his command. And settle in for the ride because he will probably deny, downplay, try to shift focus, and otherwise worm out of his situation. This is WAR. Take no prisoners just keep repeating that you have all the proof you need (and don't tell him exactly what), he needs to make a decision right now, and that you will never be a part of a marriage with more than two people in it. It may take time, but it is an either or situation. No, he can't have time to think no, he can't say good by privately, decide now or leave.
Many BS think that by using hardball tactics like these, they will "drive away' their WS. Not true. You WS has already left you. They already have most of their body out of the door leaving you. You cannot love them or nice them back. If you could, then this site would not exist. You have to become strong and frankly, terrifying. Shock and awe, as it were. And if he stays, I still would not let him into my bedroom until at a minimum the NC was done, I had all of the passwords for all of his electronic devices, social media, etc., and he had presented me with a clean STD/HIV panel (which unfortunately, you are going to have to go in for testing for as well).
Look. Serving papers doesn't mean that you HAVE to divorce. You can stop that process at any time. But having them, and showing the WS that you are utterly determined that this affair is going to stop now Or Else, is like throwing a bucket of cold water on a screaming child. It will shock them into awareness like nothing else. (((hugs))) Please think long and hard about this. And come back often for support. We're all here for you.