I voted YANBU, because while I think what your husband has done is likely completely reasonable, it sounds like you're feeling anxious and unsure about it. Could the two of you sit down and talk about finances and the future, some time when you're both a bit relaxed and have some privacy? It might also be a good chance to talk about your going back to work, as you're thinking about it.
I switched fields in my late '20s, a different situation as I didn't have children at the time and I hadn't formally retrained, but I also took a pay cut to move to my new field. There are exceptions, but it's pretty common to have to "prove" yourself again and show you can do the specific work and demonstrate that you have experience in the new field. A lot can carry over from prior experience, but not everything. I moved from investment banking to financial technology, and did my "retraining" on the job - it took me about 18 months to get established in my new field but it was worth it. (I was a bit anxious at the time that the deviation in salary would look odd or negative to future employers who'd judge me before I had a chance to explain it, and occasionally it does, but most employers are much more flexible and understanding about non-traditional career paths than they were even 10-15 years ago).
For your own work/career/reentry plans, there's a "Back to Work" board here on MN, with lots of good advice and support about things like writing a CV, getting references, boosting self-confidence, retraining, etc. after being out of the formal job market for years (mostly SAHMs, but some others) - you might find it helpful: https://www.mumsnet.com/talk/going_back_to_work