I'm curious WHY your wife is upset about you not throwing them under the bus? Is that the reason she still mistrusts your timeline and feelings?
Sometimes, it's easier to stay in a "safety zone" emotionally when you've been betrayed so completely. After being deceived and betrayed repeatedly over the years, she may have concluded that not trusting you is safer for her. She doesn't have to make herself emotionally vulnerable or available to you that way. She can keep you at arm's length, and any emotion she doesn't want, such as trust or forgiveness, she has a built-in reason to push it away. In essence, it is her shield against you. You cannot devastate her again if she doesn't let you in enough to do so.
Right after D-day, I defended the AP quite heavily and took steps (including hiding my NC letter from my spouse) to protect and defend the AP. There isn't a word in the English language that adequately describes the depths of the pain my wife felt after D-day. She was devastated to her very soul. Every second of every day was anguish for her. Here, her husband, who up until then had always been a loving husband, suddenly turned into someone she no longer knew. I was an angry, hurtful, petulant child, emotionally speaking. And the icing on the cake was that, while she was in agony, I was worried about how the AP might feel, how she might feel abandoned or unloved by me. None of those thoughts did I have for my wife. I tried to. I wanted to. But my head was so far up my ass that even I no longer knew who I was or how I got there. While I "got over" the AP pretty quickly, it was almost a year before I could think of her without guilt. It was horrible. *I* was horrible.
I know I'm not alone in that. I've read many stories about other WS's who defended their APs. We usually turn the tables on our spouses and try to blame them for our misdeeds or try to justify what we did and frame it as a lack of something on their part. It's a common thing we do, part and parcel of having an affair, I suppose. But for our spouses, it is salt and lemon juice poured into the wound accompanied by an evil intention and a complete lack of empathy or care. It feels very personal to them, like a personal attack against them (and it is), while the WS remains clueless, harmful, and protected by (you) the WS. That is where a LOT of the trauma from infidelity comes in. No matter what the trauma is, it is always made worse by the inability of the other party to recognize, admit, own, and attend to their actions and emotions. It honestly makes the person who has been wronged (BS) feel like they are going crazy and being punished and tortured at the same time. Again, this is soul-level pain. And that kind of pain changes you, often in ways that you yourself may not like. But change must happen because, after that much torture, your mind doesn't always want to give you the option of ever trusting again. And that applies to everyone, not just the betrayer.
At eight years out, I never think of the AP unless there is some reason to. Sure, little things might jog a quick memory (a song, a place), but those memories are painful, hurtful, and unpleasant. I certainly don't have feelings of love for the AP, nor do I hate her, although I hate what she did much in the same way that I hate what I did. At the end of the day, she was a very broken person, and I was a very broken person. Now, I try to do better, be better, love myself more, and show my wife through my actions that I do love her. My only wish for the AP is that she gets help and attempts to change and grow. Not because I have feelings for her but simply because she's human, and we all deserve to love ourselves, even when we've failed everything so spectacularly. So I don't hate her, but let's be clear: I never want to see her again, and if she ever decides one day to try and pop into my life again, there will be immense anger and disgust on my part.
Part of your particular problem/challenge right now is simply the fact that you are still battling with anger and defensiveness, and both of these are clear signs of self-protection, which, again, is not trust-inspiring for the person you hurt. People with something to hide often do their best to push back, and anger usually accompanies a guilty mind. To be fair, most people don't like being blamed for stuff, even when we did what we're accused of, and I think that's part of us trying to protect our self-image. We don't want to be that person, so our heads push back. But responsible and empathetic people will hopefully take a step back at times like those and admit what they did. Note that it doesn't mean that everything you are accused of is true! For example, your spouse may accuse you of sleeping with someone that you never slept with. You don't need to lie and say, "Yes, I did," when you didn't, and that's honestly just another form of manipulation anyway. You need to show empathy and understanding for their feelings in that moment. Sometimes, the answer is, "While I maintain that I did not sleep with her, I also agree that I definitely would have under other circumstances, and had I done so, I would not have told you or felt the least bit guilty about it at the moment." It's not about acknowleding the truth, it's about acknowledging their hurt, their suffering, the fact that their life has been destroyed by your lies and misdeeds. It's owning the horror of what you did to them and showing them you actually understand and will own how awful you were. You have to throw yourself under the bus. And that's very hard to do, especially when you want the other person to love you more, not hate you more. In truth, throwing yourself under the bus usually allows the BS to consider any vulnerability with you again. Truth heals many wounds. Understanding and suffering along with them (and making changes so it never happens again!) helps them heal the most. It lets them know they aren't crazy. It lets them know you actually have a soul. It lets them know you aren't lying because no one would admit to being that awful unless they were really that awful.
I wish you luck. I don't have a magic formula to make your wife love and trust you again. Only you have that. But as always, it starts and ends with you. She may never trust you again, even if you change, even if God personally vouched for you. That's a consequence of infidelity. And it sucks. But it is what it is. You can still help protect yourself from that pain by loving yourself more. RuPaul famously says, "How the hell are you going to love someone else if you can't love yourself first?" And that's really the crux here. She can't love you if even you don't love you. So, work on that. You'll need it no matter the outcomes.