What the hell?!?!

For months the fights have been getting further and further out of control...literally MONTHS. I was supposed to leave in April, and then in June (without telling him of course), but he got hurt at work (supposedly) and couldn't walk, so plans got pushed to the wayside so I could care for him. (Now I'm not even sure he was actually hurt...he sure got over it quickly when he wanted to). He seemed to make some changes while he was injured; becoming less of a shithead, and more of a somewhat decent human being....at least that's what I thought at the time, but looking back I realized that he wasn't being better, the kids were gone (at my sister's for the summer) and I was focusing entirely on him when I wasn't at work. He still had moments of treating me like shit; although he (and I tbh) brushed those off as pain and frustration on his part. Once the kids came back home for the school year, things fell right back to usual. We were fighting, horrendously at least once a week....him not letting me sleep, him being an abusive jerk (actually, those fights continued throughout the summer as well; on weekends when the girls were home, but again, I brushed them off as just frustration and pain, although in my heart I recognized that it was consistently happening whenever he was not the center of the universe. And really...after 18 years, haven't I learned ANYTHING?!?!
Anyway, the fights got so bad that I finally, for the first honest to goodness time, told him I wanted to divorce. I cannot, nor will I take this any longer. This time culminated in him making a huge, scary scene in public...in a Walmart parking lot for God's sake, which resulted in somebody there calling police--he had left before they got there, but really how freaking humiliating!! I told him that I feel NOTHING for him, or for our relationship any longer (to which I was told I was being abusive); there is no anger, no fear, no pain, nothing...absolutely nothing. Then I got really sick. First it was an enlarged spleen, elevated wbc count; then it became a terrible bout of pneumonia which I am still struggling to get over--after two courses of antibiotics and over a month of exhaustion and coughing (although I can, thankfully, breathe again).
Suddenly, about three weeks ago, he became someone totally different. Now, granted, he isn't coming home until late every night--later than usual; he bought another car he is currently working on, and he still expects me to fix his food whenever he shows up and take care of his other crap if I'm off work, but overall the tempo in the house has been different. I keep waiting for the other shoe to drop and him to go back to being an asshole full time, but so far that hasn't happened. There was one small glitch last Friday, but even that surprised the hell out of me because he didn't keep that argument going well into the night and for days afterwards. I'm just not sure what to think right now. Part of me is terrified; this dynamic has thrown me off balance. What could he possibly be cooking up in his brain to do next?! Then I feel like a fool because I sound like a paranoid myself.
I am still following through with my previous plans; applying for places, researching legal ramifications, cleaning up credit issues and trying to save money, even joining the state's cigarette cessation program and getting patches to quit smoking, taking the girls to counseling, the stuff I needed to do. I've even signed up for a few groups and made plans to have a "girl's spa day" with my girls, my son's girlfriend, and my sister (although he has NO idea I've done these things...any of them). But, in the back of my mind I'm just sitting here...waiting for the other shoe to drop. I can only imagine what he's got in store for me. and isn't that freaking sad that I've turned into a paranoid individual; always seeing shadows and things that go bump in the night, even when they may not exist?!