She has been a lot more stable apart from here and there. The focus of her IC shifted from finding out why she did it to help her cope with the outcome (separetion and divorce). She has been a lot more calm since she started, especially around kids
What your wife has been doing is called "white knuckling". It's a phenomenon where people essentially put on a brave face or act in a certain way even though it is against what they are truly feeling and wanting to do.
Both cheaters and betrayed spouses are known to do this.
So while your wife has been putting on the face of "getting better due to IC", in fact, she is just hanging on and acting as if she is with the program hoping you will change your mind, and doing whatever she can to turn your head around, including pussy-bombing you etc.
What you have noticed recently is that she "lets the mask drop" meaning she cannot keep up the pretense of behaving like someone who isn't utterly self-centered.
That's when you get called an asshole, she decides she doesn't want to divorce even though she has been outside your marriage, and that snooping through your phone is something she should do.
Yes, whe share the same IC. The outcome (divorce) is their now focus.
Respectfully, unless you are sitting with them, you have no idea whatsoever what their focus is.
If your wife trusts this therapist at all, she is telling the therapist things that are inconsistent with what she is telling you.
You don't know if the therapist is telling her: "He's just mad now, give him some time to calm down."
You just don't know.
I know you are going to do what you are going to do. I hope I don't offend you, but I will re-iterate: Therapy is useless for a cheater who isn't hellbent intent on changing themselves, so much so that if the therapist doesn't hold them accountable, they will fire the therapist.
I will also re-iterate that sharing a therapist is a huge mistake.
Even making the huge leap of assuming the therapist is intelligent, decent, has the right outlook on cheating (accountability and truth above all), the therapist cannot serve two masters with different goals.
Your goals are different from your wife's goals. You want to get out of infidelity (which mean living with a liar to a large degree), and have a trusting life with your wife, being able to look yourself in the mirror in continuing on with this woman.
Your wife wants to go back to when you didn't know who she really was and "get out of trouble" so nothing really changes for her.
Her actions tell the truth, not her words. And if she is telling the therapist different she is lying to the therapist.
***
Please understand this: As Tushnurse stated, the biggest problem is that your wife's reaction to any situation where she is facing pressure with you is to lie.
I would like to add to that: she has incredibly bad judgement, which puts her in the situation where she feels she needs to lie. She see a right choice and wrong choice, she deliberately makes the wrong choice and then uses lies to evade consequences.
Trust first, then comes healing. Good luck to you.