But it does annoy me, when DHs are quite happy for their wives to be at home when it suits them, only to suddenly start demanding the wife who once had the same earning potential as them, suddenly take on some menial, dead end job
I agree that it's all too usual for the woman to take a hit to her career, finances, and pension because she's generally the parent who stays home.
But the OP has some time now to start to deal with this situation, by doing some retraining/reskilling, so that she can start to get back to her career - from what the OP says, she had a good career & skills 10 years ago. But we all know that the workplace is designed around male bodies & lifestyle (ie arranged around men - who don't get pregnant obviously!) and it is really tough getting back into the paid workforce.
All the more reason for the OP to start doing that sooner rather than later, although she may have to start in a much lower grade of job than she is used to.
But it also sounds as though her DH is pretty hopeless with planning & finances - it looks like a bit of "learned helplessness" - so if the OP is really "managing the household" (although she has said she's rubbish at it) then she needs to take up some control, do the budgets, and then have a serious conversation with her DH about their family finances and budgets.
Show him what likely income she could bring in, and what the costs of that would be ie childcare; a cleaner; the DH taking on more of the household management ; sharing of tasks.
As the OP says, the money has been tied up with emotion. Yes, money in families is emotional. All the more reason for the OP to take a step back, and try to offer her DH the facts, as fairly and objectively as possible.
Then they can both talk about their feelings: I think the OP's DH may well have something to say about the stress of having all the financial responsibility. How do they compassionately& lovingly balance that against the OP's expressed being "terrified" of working/childcare?
There needs to be give & take, but based on the FACTS of their finances. And not their children's inheritance. THat idea is shocking.