WS here. I disassociated for months prior to and during the affair, and it greatly (negatively) affected my ability to own and understand my part in the affair during R. It took me years to work through it. I'd like to offer any advice I can to both help you to understand it, and more importantly, navigate it as it relates to the affair.
As others have said, it felt like watching a movie, in a literal sense. I was aware of myself, aware of my thoughts, but it was as if there were "two of me", and the person who was speaking/moving/feeling/doing things was someone else. It felt as if I was just a few inches behind my body, not really existing, but just watching what this other person was doing and living their life. I know how incredibly silly that sounds, and if your alarm bells are going off, I don't blame you. I would think I'm full of shit too, except that I lived it.
I won't go into all the ugly details now. Suffice to say that after years and years of hard work and therapy, we concluded that the abuse and neglect I experienced as a child affected me. I have a condition that is similar to DID (multiple personalities), however with me, instead of being "other people", my own personality fragmented. When you are abused repeatedly, you learn to "go elsewhere" or "be someone else" in order to survive the ordeal(s). I have a 6-year-old me, who is the abused and scared little boy, the 16-year-old me, who is the protector but also the super angry and retribution one, and he was the one "driving the bus" during the affair. And then there is "me", my current self. There might be more. From the same elements of my life that caused my personality to fragment, I also have been diagnosed with C-PTSD and depression.
Regarding memory issues - these are very real. This sucks, because WS's lying about remembering things is also very real. So it is almost impossible to tell one from the other. If you google "trauma and memory loss" (PTSD, depression and DID all fall under that same umbrella) you will find that memory loss is very common in people who suffer from trauma, and in most cases is related to a trigger of some kind. And it is inconsistent. So for example, maybe the WS went to dinner with the AP and then had sex in the car. They might remember every detail of the dinner because there was nothing triggery about that, but not remember the sex afterward because maybe that triggered memories of abuse in their childhood, or even simply the guilt and shame of being a cheater in the present.
The real reason I bring this all up however is that it made R so very difficult for both of us. My guilty heart and mind just tried to glom on to any excuse or justification that I possibly could in order to try and "make it not my fault". The story in my head was, "If I was not in my right mind, and if someone else was driving the bus, then how can *I* be held responsible for the things I did while I wasn't playing with a full deck?" And that's a great question. How the WS answers it makes all the difference.
The bottom line is this. Even if your WS was completely disassociated during the A, the choices they made, and the actions they took, were the responsibility of the person who made those choices and actions. Themselves. True, they might not remember some details, or might not even have "been there" for the events, but the choices they made still came from the same brain, and the same body. Even if we completely excused their actions due to mental issues, the fact would still remain that an affair occurred, and that the BS was harmed, and that the WS was the cause of that. A normal, healthy person would say, "OMG, even if I didn't mean to hurt you, I did, and so I need to own that and make it right". A broken, wayward person will most likely lack the empathy and ownership required. So what you get instead is lies and bullshit as they bury their head in shame, avoid conflict, live in denial and remain in a selfish, CYA mode.
If you don't mind, I'd like to offer you this advice, take it or leave it as you need. Don't focus on the memory or lack thereof. You've already proven these things happened anyway, so there you go. Instead, focus on your spouse's ability to own what they did, to empathize with you on the trauma it caused you, and the amount of effort and desire they are willing to put into making things right, regardless of their memories or intentions. (If I threw a baseball and it broke your window, whether I intended to break the window or not, it is still my fault, and your loss, so it is my burden to apologize with empathy and to pay for the window. That should happen, even if for no other reason than my own self-respect and accountability. If I tell you to go jump in the lake and that it's not my fault, then that is not acceptable). Judge your WS not on what they say or remember, but on what they do, and how they react. Words are easy to manipulate. Actions are not. Their actions will tell you everything you need to know. If your spouse is showing sincere emotions, accountability, contrition, authenticity, empathy and care, it will be obvious. It will be more obvious when those things are lacking as they are now. As long as they continue to be defensive, angry, blaming, avoiding, living in shame, or just clueless, they are still not safe to be around, and not yet at the point where they need to be in order to be healthy and safe.
