So I can definitely see both sides.
My family has really high medical expenses, and it is all for routine maintenance type stuff due to all 4 of us (2 adults, 2 kids) having genetic conditions or chronic conditions that require a test or 3 a year, each, plus associated pre and post appointments. It does add up, and it sucks. But.... what are you going to do? Not get the recommended follow-up care? So we just plan for hitting definitely our deductible every year, and probably our OOP Max. Its built into the budget and its been consistent, so it isn't a shock.
That said, knowing this, we certainly take medical budgeting strongly into account when considering job changes. For example recently was offered a job which I did not accept for many reasons, but one of them was that I would be offered very crappy insurance. Thus I could no longer be on H's insurance, but he would still pay the same rate, plus I would now be paying separate premiums and separate deductibles. You learn to account for that and plan accordingly.
Now in your case, yes I would be frustrated too. My mom recently had the blood in urine thing, and due to a specific increased risk of bladder cancer for her (due to genetic form of cancer she has) they did the whole 3K test. For her it makes sense. I was offered the blood test/US and my doc suggested I decline it because it leads to exactly what you had happen- you find a tiny bit of blood, go do an expensive test, and there is no data to support that it saves any lives, it just costs a ton of money. So I declined to even do the blood test/US.
Have you ever brought this up at all? Could you bring it up in the context of her therapy, and ask if you could come with her to therapy and talk about it with a neutral 3rd party present? Sort of like "honey, your medical expenses have been high for what ended up being nothing, I am worried this is an expression of your anxiety" kind of thing. Similarly, did you speak up in the specialist's office? I would have piped up right then and there and "piled on" with the doctor who was saying she didn't need an additional test.
Quite a bit of research out there supports you that all these extra tests do not improve outcomes. Unfortunately when you look at them one at a time, it is easy to justify it and to not know if you should or shouldn't. I feel like I have had to be pretty conscious about resisting, because for a long time I had insurance that covered everything, so i just said "sure" to whatever the doc suggested. It is hard to change that habit.