Gaslighting is by far the worst, imo. I remember driving to visit people and XH would pick a fight in the car. Then he walk into the party like Mr. Charming, and I was left to put myself back together, totally confused as to why that even happened. I finally started driving in a separate car, but didn't realize why I had started doing it. This was during the pre-BD ramp up.
The main thing that happened as the verbal abuse ramped up was that I backed away. It was like he needed to fight over nothing. There were plenty of places we could justly disagree, but he never settled on one of those, just stupid stuff, and always making something he could easily have done, too, my fault for it not being done. My result was that I did less, withdrew more, and did my own thing since he was not available. Addressing the situation was no help because he lied and denied.
So I have to say in my case, I tried to find out what was wrong, I could see and feel it. I was gaslighted and told I was imagining things. So my only choice to protect my sanity was to back away.
After BD, overt monster got told that he had no cause or right to speak to me that way, that I GET to have my own opinion, and that he treated complete strangers better than he did me. I learned really quick not to argue, just state my truth and repeat same, no matter what else he said. He didn't monster very long as it's hard to be the only one in the argument, but you need a very strong sense of self. At one point, pre -BD, I wasn't sure I had any sense of self left, I was so confused at what was happening, but after BD it made some weird kind of sense, and my sense of self came back to the surface.
Gaslighting can make you doubt your own reality, it's why it's a favorite of abusers. It's why the LBS sometimes becomes a researcher and even a stalker, trying to find what is real and what is lies.
What I learned is whether XH ever comes around, or if I find anyone else, or even in my friendships, if I feel like my reality is being manipulated, they get one chance when I directly address it to them. If it happens again, I'm out of that relationship. Heck, I do not tolerate it at work. I'm still surprised I was never fired, but my boss seems to respect me for (quietly) calling him on his BS in a factual way.
I'll take recognizing gaslighting as a gift from MLC. I had never experienced it before, to my knowledge, but I sure see it when it happens now.