Oh, Matt. I'm sorry you've hit part of the rollercoaster that slowly goes up, with a quick drop on the other side- with a few twists and turns for you to endure.
I realize that when we see a part of our spouse we remember, we tend to attach those forbidden expectations. It is so hard not to.... but don't.
I know you knew where it was going to go next, and that you'd see a different side, as you stated, but I think that you saw her be rational hoping that she would let you handle the tax situation.
Matt, don't let her get you riled up! Of course she is going to react that way towards you. She has been terrible to you. She has a very long road ahead of her before she really starts to come around. I know you know this. It can be very difficult to really accept this. Knowing it and accepting it are two different things. I think you are doing a great job, Matt. I feel for you. She has not realized what she has with you. Maybe she never will. You can't try to fix these things.
I would just let it go. If she wants these things, send it to her. Maybe put a note on it, "Copy XXX was sent on XX/XX/XXXX." You already told her you were taking care of it. She knew that. She tried to re-engage the next day in MLC fashion. Don't do it, Matt. It was already addressed. If she wants to freak out, it is not your problem. I wouldn't even respond outside of passing along necessary information without emotion (I'd probably do it through the mail, but that's me).
It was wonderful you had the opportunity to have the nice convo with her! I think you did great! I also think your expectations are much less (atta boy!). You need to check out as soon as monster checks in.
You said your w has zero coping skills. I think that many mlcers are sent to this crisis, because they never had good ones to begin with. I think that plays one of the key factors in this. Most have childhood issues, and were never taught how to "cope" with them. Or, for whatever reason, just don't have coping skills. Add to it a lifetime of not coping with things, it gets overwhelming and any coping goes right out the window, and.... welcome to Midlife Crisis Land! Our lucky spouses get a free lifetime pass. It includes free family pack to Crazy Land! All are able to leave whenever they wish... they just have to exit through the Maze of He11.
Keep your head up, Matt! You are a great guy. She needs to bounce around for awhile in the pin-ball machine. Let her, you can't spot it.