I think Butforthegrace is onto something:
My gut feeling is that your WW's issue had to do specifically with a longstanding feeling of sexual inadequacy, a subconscious desire to feel like a powerful sexual woman. My thesis is that she had suppressed that for years, to the point where she was possibly even unaware of it, but it was so buried that she could not pursue this with you because you were part of the cause of her feeling of sexual inadequacy.
I am going to expand on this hypothesis. My whys were different than your wife's and the situation was different. But, I do see the areas in which polarization has occurred in our relationship.
I am going to take this to an example for my husband. I have worked over and over in spells over the course of our marriage to get him to talk about his feelings. Our problem has never been physical intimacy - we have had that in spades. But, emotional intimacy is a struggle. I don't think it's because my husband doesn't want to give it to me, it's because he doesn't know how. Often times, he really doesn't understand himself to be able to share in that way. And, other times, I am reaching for something that just really isn't there. (Meaning, he just doesn't have feelings about a certain topic and I am trying to get him to talk about it and he can't - it's not there)
So, what happens?
What happens is he doesn't even attempt to initiate such conversations even with something on his mind. If I broach it, he shuts down. Why? Because he doesn't want to explore emotions with me? No, because he knows I want to so much that if he does it wrong, or opens it up a little bit I am going to run with it. Or that I will want him to do it more.
So, taking your wife's possible view point. Sex is the major thing for you. It's super important to you. She has spent your marriage trying to keep the expectation down, like my husband has. If she suddenly wanted to try to be different sexually and opened that door but then didn't like it - that would be a huge disappointment to you. Giving you a toy and taking it away. You would want to run with it, you would want more.
As butforthegrace points out - none of this is conscious. Often times, as it was for me, the affair is an escape from reality. The power of it isn't the AP. I can assure you. A lot of the power of it is who we can suddenly be and it's not authentic.
Before XHZ takes offense, I will say 100% there is no justification for an affair. It's 100% the waywards fault, not the BS's. But, getting to our whys and hows is a completely different story.
For me, what I latched on to and drank up was the AP had an ability to communicate about his emotions. He was actually (sorry for the generalization) quite more feminine than my husband. He had interests in my clothes choices or how I was wearing my hair. It was all lies and smoke and mirrors of course because he was as lacking in character as much as I was if not even moreso as a serial cheater. Like I said, he was just better at it and he knew the ways to mirror me. Again, I am not a victim, I can clearly see the ways I played to him to keep his interest as well.
I get that sex is hugely important to guys. But, for you it's paramount - top tier. Maybe even more so because you decided that you would live without certain things or actions because you love your wife. Kind of starving that part of you that gives it just a bit more edge than an H that is getting it on the regular. (I am reminded of what Dr. Phil used to say - sex is 10% of marriage, but if it's not happening it's 90%) That starving feeling you are having could easily polarize with a woman who might actually be sexual but make it more scary to explore with you. My clue here is in another post you said she wanted to resume watching porn after the A and it was okay with you. A non-sexual woman does not watch porn, especially not on her own. That doesn't even make sense.
So, Here are some things I think you need to think about more in your reconciliation:
1. I still think the sex is not the thing that hurts exactly, is the fact it's your greatest love language and she spoke that language to him. Thus, a part of you feels she loved him/desired him more. This is still about feelings and not about the sex. If you can find a way to express that to her she is going to understand it better and it's going to help balance the situation and not polarize the sex issue more. Maybe that has been worked out more, it sounds like the sex life has been being worked on.
2. The feeling you don't know her because she was completely different in the A than you have known her to be. This is where she really needs to get to the root of her whys. I mean digging past the whole getting validation thing. I mean getting specific the way butforthegrace is talking about. It's hard to unearth, I still unearth things and I don't like some of it. So, I put it away and then get it out and look at it again later, over and over until I really can process it. It is a painful process, and painfully slow.
3. Somehow during your process, and this might take longer, you need to internalize the fact this AP didn't have some magic dick or something about him that made your wife go mad. That's not what happened at all. Very little of what happens in the affair is about the AP at all. She was able to be different somehow. What was she escaping? Porn star sex? Please...if I was performing that it would mean I was really getting very little out of the sex. Its so fake. I know guys want to see our excitement, but I believe more genuinely. The fakeness is not excitement it's a performance. Why the need for the performance? Validation likely, but like butforthegrace said - likely validation that she has that in her, that power. Sure, she could show it to you, but then you would want her to show it all the time. And, she's not comfortable with that because she doesn't know if that's really her sexually. She doesn't know how to explore who she is sexually without disappointing you if she puts that away and tries something else??? Not sure, but that makes sense to me.
4. In building a new marriage, what can you do to balance out the polarization? Are you constantly lecherous when any type of physical intimacy occurs? How is your emotional intimacy? What would the new marriage look like?
You may not be at all poised yet for #4. I can't tell if you are still in recovery or truly in the reconciliation phase. But I feel like if you want to reconcile and you want to be married to your wife - which by any post that I have read of yours you do...then having that picture in mind of what you want it to look like together is the only way to build it. Who builds a house without a plan? You know where the kitchen is going to be an how large, there are reasons the masterbedroom is here instead of there...
I don't believe for a minute you are going to figure out your equation. How much asshole factor exists in your wife, or how you can control it in the future. If you want the best way forward, I truly believe it's going to have to be with getting underneath of this issue instead of looking at it head-on. You have been stuck there for a long time, it would be worth a shot. You might be stuck because she is stuck too - how well is she moving forward? Are you happy with her progress or the work she has done on herself?