Expect your husband to go through a wide range of feelings. Expect him to want to "come back" to you one moment and then "go to her" the next. But, as you probably know by now, once the clock is ticking and you are in divorce all expectations you have about him must end. You need to emotionally detach and expect this divorce... and live that way. And live happy and healthy with that.
Now, that doesn't mean you can't lovingly detach and be a friend. (Of course, this doesn't include legal and financial matters with divorce.... I believe in going for the jugular with kids are involved, but you just don't have to tell your husband that. He shouldn't know all these details. And once he finds out and gets crazed just say you are going with your attorney's council, and you must do what's best for the children... then be cheerful and change the subject. Act stupid... LOL).
One thing you need to realize. If you think your husband is acting insane now, wait till he starts suspecting that you may have other men in your life!!!! I have a strong suspicion that he may hit rock bottom then. From everything you've described this is a guy really struggling with letting you go in spite of being completely addicted to OW.
What helped my husband hit rock bottom was my detachment and his suspicion that there might be another man in my life. I was very firm about not "seriously" dating until the divorce was final and I had plenty of time to get healthy and work through any baggage. I told him I wanted to make sure I was healthy and baggage-less and any potential boyfriends have worked through any past baggage as well. Also, I pointed out that I had no interest in going through the crazyness of a "rebound" relationship.... but... on the other hand. I'd also tell him about how surprised I was by how many men seem to "know" when a woman is in divorce. It's like they have radar and swarm. I would speak about this with a big smile and would offhandedly say things like, "I never realized there were so many great guys out there!" But I'd be careful not to make it sound like I was trying to make him jealous. I'd just say it like I was surprised. I also said things to him, really surprised, "Wow, I never realized how attractive I am?" (Hee hee!!!). But I truly was going out with girlfriends and talking with guys. I flirted, had fun with groups of women and men, even had a couple of "crushes" (nothing beyond friendly hugs and talk).
But these male friendships were great, because they helped me realize there would be life beyond my marriage. And they also helped me feel better about myself after having been displaced by a woman 10 years younger and much more professionally successful than me. And I felt great about myself, because I didn't get seriously involved with anyone. I was so proud of myself for wanting to be emotionally healthy, fully unattached and eventually, someday have a great relationship with the intention of marriage and "growing old together." I know that probably sounds idealistic and even old-fashioned. But thinking and living this way... while still having a lot of fun helped me enormously.
Anyhow.... one thing recommended by the DBing coach I spoke with was to be mysterious. I think this was wise advice.
I do have more to say... but gotta run!
There is no arriving, ever. It is all a continual becoming.
