Heter
Therapists are people you interview, much like nannies, housekeepers, etc. you ask certain open ended questions, listen to how they answer.
Most of this is done over the phone or during the first visit....they are not just interviewing you!
Do not be a complacent consumer, ask questions during therapy. I asked for 'homework' between visits...because just 'waiting' for the next one wasn't doing it.
Ok, so when you talk to your MD you ask for a referral to a psychiatrist who would know Depression....almost everyone does!
When calling for self, ask for someone who is familiar with dealing with situational depression. Then when you find one you fit with, work on self and relationship...in that order.
Same with wife. You both need to work on yourselves then the relationship...the order which things occur.

It just may be there IS an added component to your wifes depression...such as marital, adhd, pms....
When I was seeing a pscyh for dep he prescribed a drug to give a bit of a boost, to get me going, since I was dragging my arse around. He prescribed dexedrine. I took it, promptly felt sleepy.
I called and he asked if I had ever been diagnosed with ADD...not officially....dexedrine is what they give kids with ADD and ADHD to settle them down....at 7 in the morning I took them and instead of feeling more invigorated, I wanted to nap....not the usual case when taking speed.

BY the way, you have to keep interviewing...it may take a dozen interviews or a hundred to find a good fit...but, you do not spend a year with each one, you spend one or two phone calls or visits...to see how you feel with one another...and if they feel they can help you. You may not be expert, but, you do live your lives. Do not be a pushover, on the other hand, talk it over with them...do not be stubborn! Listen to why they believe what they do. Look up a NAMI organization and see if there is a chapter near you...maybe they have psych they can direct you to, or your own local APA, if you live in America...Canada have their own version, as does UK.

A therapist can only go as far as a patient will allow them. If a patient is only wanting 'support' and not the 'hard stuff' they will sense that you are not ready for the hard stuff and steer away from that till you are. Giving you bits and pieces until you are ready for the 'solid' food. When in the middle of the MDE I followed my therapists lead...when less so, I wanted more...and pressed for more.
Homework...give me something to do, some exercises to do when at home, not just sit and wait for the next appt. so I can vent. Give me something to 'think' about. It is like here...the stuff here gives me something to think about...mull over. The questions people have asked me, or questions they have brought up in their own threads, made me think in so many different ways...questions I would never have thought to pose, for I am not them.

I do wonder why your wifes anger began in 1998...what may have triggered a change in her behavior....or reaction to situations.

Another BTW:
To get a proper diagnosis...not that I discount MD's. BUT, try to find a Psychiatrist with a specialty in depression...most are these days.

I Became Insane
With Horrible
Intervals of Sanity

E.A. Poe