This is profound, and I think very well could be at play here and in many of the sitches on this board: "I also think it has to do with her equating me with her own long-suppressed anger and dissatisfaction with her own life."
The "HOW" takes practice. (Dare I say, especially for a man who has lived up to society's expectations and norms of what a man is his whole life.) Schnarch suggests some techniques (hugging 'til relaxed, eyes open ML) but they require that your partner wants to work with you. What I'm hearing from you is that you first need to start opening up in general without measuring the possible outcome/reaction of what you put out there. It is NOT easy to eliminate the self-protective screening mechanism that's been in place since your childhood.
Therapy sessions by nature require that you let it flow in order to get the best help possible. You can practice there. Also, try to spend time with your W alone and TALK. About anything. Just TALK and practice letting your words reflect who YOU are.
By the way, be prepared... Being open and intimate makes you more vulnerable, but the rewards and connection with humanity is SO WORTH IT!
