Depression, true depression is not selfish, and not by choice. Even if you are the cause of the situation you’re in. Honestly, I the lack of depression in “most” WS’s is a strong data point for me that solidifies my opinion that the overwhelming majority of WS’s, (even very remorseful ones), never truly get the true depth of destruction and life long damage they have inflicted on the BS. If they did, I think depression would be logical. But it seems to not be the norm. You’re in a very difficult situation, and have been for a very long time, self made, but that doesn’t make it any easier.
I will disagree somewhat with others here about your husband crossing boundaries. I do believe that “your” therapy is “your” therapy, and should be private. BUT! After an affair, you give up all expectation of privacy or should. Should he be able to request you to record all therapy sessions so he can listen to them? Of course not. But if when my wife was still in therapy, and she had recorded her sessions, and I found them on her phone, you can bet your a$$ I would have listened to them! Cheaters are liars, and master manipulators. Not all therapists are the greatest, and some can certainly be manipulated as well. I do believe my wife was manipulating her therapist in the early days. She actually said this to me about a month after d-day -“My therapist said that I have apologized to you in every way possible and there is nothing else I can do.” I told her if that was her opinion, then she could pack her $hit and find a new home. Now, did her therapist actually say that? Maybe she did, but what information was she going off of? The truth? The whole truth? Part of the truth, and part lies? My wife found a new therapist. I would use any data point I could to find out if my wife was being truthful, and not manipulating me, and I would feel ZERO shame or guilt about it. You lied to your husband for 20 years if I remember correctly. That is an insanely long time. You lied to him for almost the entirety of your marriage. That is a big mountain to overcome.
I agree with you letting him have his mom for support. Since he told her all the details, can you really blame her for treating you a bit differently? I mean that makes sense, doesn’t it? I mean I would be thankful she even speaks to you. But you do need someone that you can talk to. If you don’t, that will make pulling out of the depression that much harder.
You made this mess, but just because this is all your fault doesn’t mean you should have to live in limbo forever. I’m not telling you to stay or leave. Only you can make that decision. It is true there are some people that can’t get past this level of damage, and that doesn’t mean there is a single thing wrong with them. Infidelity doesn’t deserve forgiveness. I am a bit like that I think. My wife’s affair was 6 months long, and she never broke a boundary after d-day. If she had contacted him just once. Just one text, anything. I would have thrown her out. But there are plenty of people here that had their WS continue their affair after d-day, broke no contact many times, multiple d-days, multiple affairs, trickle truth, etc. They still stayed, and some able to find reconciliation, they are capable of more grace and forgiveness than I am. That doesn’t mean they are wrong, nor am I wrong. We are just all different people.
As WILDLY UNFAIR as it is, at some point the BS has to put in the work, or divorce. Have you asked him if he would prefer it if you left? Have you told him that you think he might be happier without you (if you think that)? Maybe he is never going to be able get past this and stay with you. Maybe he can in time.