I'm sorry you're going through all this — it sounds very painful. I'd like to reflect something back to you, if I may.I have been apologizing everytime my wife has felt insecure or upset. I have given her far more freedom than she has given me, all on the premise that I was hoping she would be happy. But she turns it around and says I only gave her that freedom so I can see my gf. Well, that is part of it, but I do legitimately want to see my wife happy
In the above-quoted post (emphasis mine) and the one before, you mention some version of wanting to make your wife happy many, many times. I wonder if that's been a pattern throughout your relationship, and not just since you started practicing polyamory?
Of course you want your loved ones to be happy instead of not, but the reality is we can't make other people be happy — we can't be in charge of the emotions of other adults, (even ones we've been married to for decades! )
Your wife's happiness is up to her, not you.
So it's not surprising that all your attempts to "solve" her insecurity and upset feelings... aren't working. Instead, you're hiding the truth to try to avoid her getting upset, and she's snooping on your private communications with your girlfriend (YIKES! ) to discover the deceit and end up even more upset.
It's understandable to prioritize the 23-year-long-with-kids relationship over the year-long relationship, sure, but we can't escape that there's another person here whose happiness is affected; do you feel responsible for your girlfriend's happiness, too, or just your wife's?
(From your previous post, it's clear you DO care deeply about your GF and her family, I'm only asking that question to follow it with this one):
What about your happiness? Where is that in all this?
It's great that you're doing both individual and couples counselling — I hope it's helpful in understanding and healing how you relate to each other.
I hope you'll consider exploring the question, "Do I put my wife's emotional needs before my own? How do I stop doing that?" in counselling, because it may be a root cause of all of this mess.