Maybe it's time for a scripted conversation with her, a sort of Hail Mary to try to get off top dead center. What I'm suggesting is a considered letter that explains carefully that you are not healed, that you want to heal with her, and what it will take to heal. You would print it out, but sit with her and read it to her, in person. You can then leave it with her to contemplate. I think the eye contact while you read this is important.
By the way, has she read "Joseph's Letter"? You can find it in the Healing Library. If she hasn't, you might include a copy of that with your letter.
What happened in year 1 was that, due to a combination of bad advice from you MC (and her mother), and you being confused and backing down in the face of pressure from your MC and Christian friends, the two of you, together, took the wrong path. You took a path away from the direction of healing. You took a path of rug-sweeping. As an unsurprising result, 3 years have passed and you are not healed. That is almost always the result of rug-sweeping.
Evidence here on SI suggests that, for most BS's, in most cases, the path to healing starts with 100% total transparency by the WS to the BS, about every intimate detail of the A. Indeed, this is the specific advice in the Linda MacDonald book.
There are three reasons for this. First is the "intimacy hole" that I discuss above. Currently, your WW and her AP share an intimacy cocoon that she has intentionally withheld from you. She is protecting their intimacy over your marriage. Those intimate moments were moments that she vowed in her wedding to share only with you. In ways, she shared greater intimacy with him than you, because he knew the truth of what was going on while she was lying to you and concealing the truth. No matter how painful those details, most BS's find that the benefit from the restoration of complete honesty outweighs the pain of the details.
Second is the mind movies. Until a BS is certain they have all of the details, their mind races around creating "what if" scenarios, many of which are based on the partial information that they do know. It's pure hell for a BS. A perfect example is your Sherlock Holmes deduction about the sexy panties. This is a detail about which you are very likely correct, but she has refused to corroborate it, leaving you flailing with your mind movies. They won't go away. This is a feedback loop that can only be stopped by transparency. Bottom line, it becomes impossible to heal if you don't know what you're healing from.
The third reason is basic decency and honesty. To facilitate her A, your WW lied to you and gaslighted you to an extremely cruel and wicked degree. The way a liar makes amends for lying is to tell the truth. The way a spouse makes amends for lying to a spouse is to give the lied-to spouse his own agency to make his own decisions about the marriage in light of the unvarnished truth. Disclosure at this level is the authentic, honesty that is the bedrock of what it means to be married.
I think you spell all of this out in a letter that starts with something like:
Dear Wife:
I think you have noticed that I'm having difficulty sustaining emotional closeness with you. I feel my love for you eroding, and distance between us increasing, and I am concerned that our marriage is at risk. I love you, I enjoy your company, and I want to save our marriage, but I cannot do it alone.
The problem is of course your affair. I say it that way because the problem is not me. I was injured by your affair, and I have not healed.
You made some choices in your affair, and in the aftermath, that continue to haunt me. For example, you decided to commit adultery with a man who lives in our neighborhood and has a son that is friends with our son. You also chose to do and say some incredibly hurtful things to me, both during your affair and after. Some of them continue to reverberate in my mind. During your affair, when my gut was telling me something was wrong, you gaslighted me and tried to make me believe that I was delusional. Afterwards, you answered at least some of my questions about your affair with "that's private" and similar responses, making it clear that you would not answer my legitimate questions about the affair.
Because of your choices, I am forced to now live a life in which encounter and see your AP several times per week; sometimes several times per day. Every time I see him, I am reminded that he has intimate knowledge about you, about sex with you, that I don't know. It leaves me wondering what that knowledge is. Some describe being traumatized by infidelity as being served a "shit sandwich". Part of the shit sandwich you have shoved into my mouth is the displeasure of seeing this man so frequently, and wondering about this, literally every day of my life.
Unfortunately, during the first year after I caught you lying to me and having a sexual affair with a man from our neighborhood, we started down a path that was almost assured to prevent me from healing. We went down this path due to a combination of bad advice from our MC, from your mother, and from our so-called "Christian" friends. The path we took was a path of rug-sweeping. I know now, from personal experience, that rug-sweeping results in the affair festering like a cancer in the soul of the betrayed husband. This is exactly what is happening with me.
I also know that I cannot heal without knowing the full truth of your affair. You have said that you have given me the full truth, and I think you believe that you have, but in reality what you have given me is a big picture outline of the affair, softening the edges in an effort to minimize it. You have arrogated the right to decide, for me, how much "truth" I should receive. To heal, I need to be the one in control of that decision.
To be clear, I do not believe you when you say that you have given me the full truth. My imagination is still consumed with filling the gaps between the things you have told me. What I need, which is what I think many betrayed spouses need, is a detailed, day-to-day, exact description of everything that happened, as if I were a fly on the wall observing and hearing it all. Without that, my mind is stuck making "mind movies" about various details.
As an example, I know that you demeaned me to your AP (and that he demeaned his wife to you). I heard you do so, casually and cruelly, in the conversations that I recorded. I would expect your text threads to contain a lot more of the same. Further, I know that you bought sexy panties specifically in anticipation of sex with the AP, and wore them both before and after the sex you had in our house (and, I believe, in our bed). I have been able to confirm this by piecing together various bits of information.
[By the way, has she said where they had sex in your house if it was not in your bed?].
There are three reasons I need this.
[paraphrase my three reasons above].
As to the honesty part, I want to remind you that you have told me you wish you had never admitted having sex with the POSOM. That wish worries me. Why would you wish that you had lied to me even more than you already have? I am your husband. Is it your view that a successful strategy for marriage is to lie to your spouse about difficult issues?
Also as to the honesty part, there is an unfortunate hurdle to this. This exists because of the initial rug-sweeping followed by the passage of time. You refused to let me read your text messages, and by now you have replaced your phone. The messages may be unrecoverable. I need to be honest and let you know that I am not sure I can heal and stay in this marriage without reading these. In refusing to let me read them, you were protecting your intimacy with your AP over your marriage to me. It was an additional insult and injury from your A that I have struggled with ever since. The wondering about what they said consumes my thoughts, sometimes to the point where I cannot think of anything else. This is your doing, so I leave it to you to come up with a solution.
If you are thinking of doing something like this, I think you need to have an ending. I've thought of two, but you should reason this out in advance.
"It's not my intent to try to force you to reveal anything you're not comfortable revealing. But you should know that, from my perspective, what you have been doing is harboring a private intimacy with another man that you shared during our marriage."
"I do not know whether I can heal and move beyond this so long as you continue to do this. I will have to keep listening to my heart and follow its lead."
or, stronger:
"You are free to continue keeping your private intimacy to yourself, but not as my wife. I will not be able to continue in this marriage if you feel that you prefer to continue withholding this from me. It is your choice."
[This message edited by Butforthegrace at 8:32 AM, August 18th (Sunday)]