Glad you are working on your symptoms in therapy! You are not a bad person. You are someone in a lot of pain who needs something to change and improve.
she gets indignant about it being her fault and says "Oh great, now it will be my fault that you are doing poorly because I sent you there.".
Where did she get the idea that if you make the choice to do as she requested, any symptoms you have are her fault? Have you ever blamed her for your symptom spikes? Ever told her something like, “I feel miserable now because you asked me to go to the base.”
It strikes me that both of you might need to focus more on what’s in your control, and greater acceptance of what isn’t in your control.
You can’t change her, no matter how unjust or unfair her complaints. But what you can do is focus on you and your choices. She isn’t responsible or to blame for your symptoms either, and needs to let go of the expressions of guilt for them.
If she asks you to go on base or to the mall, it’s reasonable to say you can’t do that. Right now, you may need to encourage her that your symptoms are not her fault. Give her permission to not be responsible for managing how you feel.
It may also help to see if you can offer an alternative option for time together that isn’t so triggering. Address the underlying need she has for connection with you.
She purposefully tries to get under my skin by devaluing what I say, interrupting and letting me know ahead of what I say that it is worthless.
That’s really crappy. That would annoy me too. Perhaps couples therapy could help you both learn to communicate better?
She will ignore me if I get loud, and only stay calm if the conversation goes her way.
Getting louder because she cuts you off? Understandable, but ineffective. Her shutting down once you start yelling is reasonable and fair.
When you express your ideas to her, try using *I* statements. “When you cut me off to tell me my ideas are worthless before I even say them, I feel devalued and hurt.” Then set a boundary. “Because of that, to manage my needs and limits, I will....” whatever it is that you will do. Perhaps not discuss her request to go to the mall or be on base until she can agree to not interrupt. Then actually do it. Don’t just keep escalating to be heard. Do something that helps you manage your anger and then when she finally agrees to hear you out... and, you’ll have to take turns so that you’ll hear her out too.
Supporters don’t generally say they feel like a sufferers symptoms are all their fault for no reason at all. Perhaps somewhere along the way, she didn’t get support in learning how to let go that your suffering isn’t her fault.
This may be a chance to help her learn that you mange you - with all the benefits and responsibilities that entails for both of you. This may be a chance for you both to find a new way forward, and you can take the lead on that.
As for breaking stuff, no judgement from me for doing it. I’ve done it. But, that kind of expression of anger can scare and stress out others. It’s not on her or your son. A good place to start might be to apologize to them both, and let them know you are working hard to change. Perhaps list out some tools you have learned in therapy or in reading info online that you are working to implement to better manage anger. (Talk to other parents - plenty here - and to your therapist abou an age appropriate manner to do this with your son.)
Sometimes, an honest apology, with no blaming others, and actual tangible action steps to change, can go a long ways to help others let go of resentment.
You are taking good steps toward change. Don’t give up hope!