I had the same problem with one more level of abstraction: My wife didn't know she was lying. My ex-wife lied about everything, and like you it took me years t

I had the same problem with one more level of abstraction: My wife didn't know she was lying. My ex-wife lied about everything, and like you it took me years to figure it out. Everything was always someone else's fault (it was my fault she couldn't work, my fault she didn't clean, my fault she didn't cook), she often rearranged the order of events or even fabricated events in their entirety. Like you, I caught her mother in a bizarre "lie" that unraveled the thing. On XMas eve her mother called very hurt that we hadn't come over for out "traditional Xmas eve." She explained that we just always came over so she didn't think to call and make sure we were coming. The fact is, I have spent every XMas eve with my own family, we have a tradition of having a party on XMas eve, and I have only missed it once due to being hospitalized. You have to understand the sheer madness of this. She imagined that we were going to come over, convinced herself that we had always done so, and that there was no reason to even let us know she expected us. This set off alarm bells in my head, I could see that my wife was remembering things that didn't happen or altering events in her head and this was why we could never talk about anything or reach any common ground because we couldn't agree on ground truth. Eventually I found out she had suffered some trauma, and as a result something called "confabulation" which is more or less a unreliable/false memory.