Would either of your IC's (preferably hers) be willing to spend a session or two to include both of you? Just to focus on this one idea?
My H is quite closed when it comes to talking openly about painful stuff, and he knows it. Because he knows that it is a problem, he understands when I approach him about it and he is able to take a deep breath and consciously open up. This took work on his part, though, through his own therapy and exploration of himself. His whole family is that way, and he recognizes it as a learned behavior that he has to repeatedly work at to unravel.
I think it would be difficult for you alone to convince her that her closed style is an issue, simply because you're working on several marital issues right now and it might be easy for either of you to feel attacked.
Maybe I'm wrong, though. If you have confidence in navigating this topic, I would certainly raise it. If it gets tangled up in other issues or emotion, perhaps suggest sharing a therapy session or two to discuss it.
It would be such a breakthrough for you two to make progress here.
