You have just described exactly how I have been living my life for the past 4 years. He has done every tactic you talked about and then some. We separated for 10 months a couple of years ago due to the level of abuse when I asked questions, then I moved back home and after 3 weeks of relative peace and acceptance, I found out he had been lying and had been with the AP up until 5 days before I moved back. The next 2 years, up until about a month ago, were very contentious and sometimes I had to leave for safety and stay at a hotel. About a month ago, everything changed, his whole demeanor, and now he says he understands my triggers, doesn't want to fight anymore, and he has not screamed in my face, stonewalled, used diversionary tactics that get out of talking about the affairs, called me names, or used physical intimidation to frighten me. It's like he magically changed overnight. It could be that he finally has managed to develop empathy after 4 years, or it could mean that something else is going on. I have to admit, I'm suspicious. I don't believe he can just do a complete 180 that quickly....so I'm wondering if the affairs have started up again...is it bad that I'm suspicious about that?
And yes, you are right about the anger at myself for putting up with it this long. That's probably why I'm still stuck and guard my heart with a steel wall. And since I'm almost 61 years old, I don't have that much time left in my life to waste on his bullying crap anymore. Don't know if I should trust this change I am seeing...