Stop. Look at yourself. Look at your wants and needs for healing. You write about your W's introspection. What about yours?
What, exactly, do you want from your W? How will you know if she gives it to you? How will you know if she isn't? If she delivers, how will you use what she delivers?
You say you want to understand her whys. What will that do for you? In fact, you'll never achieve a gut level understanding, but it's common to seek it. How will seeking this info help you? What is the effort doing for you now?
I keep reading that the WS should heal the BS. Exactly how is that going to work for you?
The fact is: if you look to someone else to heal you, you're looking for external validation to fulfill your need - and that never works. Never. External validation is nice to have, but if you can't get to where you want to be without it, you are selling yourself out.
You heal you. To R, your W needs to heal herself, and together you need to heal your M - but you heal you.
Homework in IC? Bah! That doesn't work for many of us. Some therapists think it may work universally - because they drive away the people who won't/can't do the homework. For example, I'm ADD, and I was untreated until I turned 59. Distractions always turned me away from homework ... but my mind did keep feeding me messages from therapy, and that helped me make the changes I want to make.
Always feel 'betrayed'? What is that feeling? Angry? Sad? Scared? Ashamed? Head ache? Sore shoulders? (I'll assume it doesn't feel good.)
The fact is that you've been betrayed. I think you've also related ways in which you've betrayed yourself.
These acts of betrayal are part of your history. How can you deny them? How can you expect to forget them?
I remember a lot of my W's A. I remember a lot of d-day. I remember a lot of healing. Those times were awful, and I have memories of being in pain. I can't help but feel some of the emotions that I felt then - but after 11+ years, the feelings just aren't close to the level that you're probably feeling now; they're several orders of magnitude less.
My point is this:
Stop trying to control your W. It' guaranteed to be watsed effort.
Think about your self, what hurts, what you want, how to heal yourself.
What your W is doing in her therapy isn't anywhere near as important as what you are doing in yours.
Healing from being betrayed occurs on 3 levels, IMO: head, heart, and gut - thoughts, wants, feelings. Put your focus there.
You may feel like you're between Scylla and Charybdis right now. One way to calm the waters is to change your focus to yourself. The sooner you do that, the better for you.