Great question, but an unfortunate situation between you and your wife. It could be something as simple as an agitated depression, but given the description you wrote above, here is my best guess: Your wife sounds a lot like a woman with narcissism. I know that term gets thrown around a lot, and its real meaning tends to get lost in the shuffle, but here is the deal: If a child grows up in a household/family that does not "mirror" her thoughts and feelings, she essentially grows up feeling worthless and empty inside. Of course, this feeling is remarkably uncomfortable, and so she develops a "plan" to cover up the feelings or to protect herself from feeling this way. Thus, she begins to compensate by not making herself vulnerable... EVER. If asked for an opinion, she does not risk exposing herself to ridicule or dissension - rather, she awaits the other person's opinion, and then begins the process of making it seem as though hers is far superior (again, this over-correction makes up for the fact that she feels dreadful inside). Too, she positively canNOT take it when feeling criticized - even in the smallest of ways. So rather than accept and process the feedback, she launches an all-out assault against the person who makes the judgment, thereby creating an environment whereby the other person may dare not make such an assertion again.
In all, she really does need some reparative therapy, whether she likes it or not. My advice to you would be to gently (but firmly) lay out your concerns and suggest that the two of you enter therapy together. This may be "safer" for her if she feels as if (at the very least) the responsibility for the marital issues will be shared by both of you rather than heaped onto her already drooping shoulders. I might also suggest a book for you called "Disarming the Narcissist" by Wendy Behary. It will help you to formulate a plan to increase the level of empathetic communication between the two of you.
I wish you well. If this really is a characterological disorder, then the road to recovery is going to be a long one for her. If you are satisfied with the response, please hit "Accept." That is the only way i can receive credit for my answer. Thanks-