"How do I 180 my wife hiding her feelings from me for 3 years and then dumping them on me all at once?"
This is not the issue. The fact that your W believes that she withheld her confrontation issues from you, is. What were the reasons why she said she didn't want to bring up issues with you? It could be because she didn't trust you. Maybe growing up she never learned how to trust. That's something to address.
"How do I handle it differently than FINALLY admitting that I have an anxiety issue and taking huge strides to address that issue?"
Have you always had anxiety issues? If so, continue therapy to get rid of them. Take drugs if you need them. Meditate, do whatever you need to to make you whole.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.