first of all, He's never been like this before and suddenly he makes a complete 180 in his personality. If I didn't know better I would swear he was on drugs. Before anyone asks, he isn't. He's tested at work all the time without warning. I have posted this, word for word, many times before in regards to my own H. I know what you are talking about when you write this. I have seen the completely bizarre behavior, too.
About the adultery; there is nothing wrong with you fending for yourself here. I did it. Well, I didn't take photos but I had a photo from H's computer of the two of them together, copies of his credit card statements with all the spending, copies of emails where he talked about himself with ow, stuff like that. In the end, you can only depend on yourself so I think you are smart to compile what you might need if this goes to a D.
Your H may very well have moved home so that it didn't look like abandonment. I remember when my H moved out he was very very scared I would file and use that against him. Let's face it, in your H's line of work he sees a lot of this and he probably has friends of his telling him the ins and outs so he doesn't hang himself totally.
He will look you in the face and lie. They become masters at it. He will continue to tell you it's over with ow, but it won't be; not that fast anyway.
It is a long, painful journey. Can you ask him to sleep on the sofa or another room just so you have a peaceful place of your own?
You will read here thread after thread, that these adults cannot be talked into stopping what they are doing. Every single spouse that posts here tried that and it did not work. He will have to come to the decision on his own. What you have to decide is what you want to do while that's going on, because it isn't going to happen tomorrow, I'm afraid.
I truly wish I had better things to say about this, but he's freshly into replay and he will act like the worst husband imaginable for a while.
I am thinking of you; so sorry this is so hard. There are so many of us that understand.
Most of us really marry only once. First love endures, even unto our dying day. And we never really divorce.