Well you’ve made up that he’s so very concerned that without her money they’ll be teetering in the brink of ruin
No, I've said that he has financial concerns about her not working and doesn't wish to be the sole earner. And pointed out to you the importance of money and what not having it might mean, because that's apparently not something you've ever learned.
And that his job is probably precarious.
No, I pointed out that being the sole earner means more than just continuing to go to work, but also having to be doubly conscious and concerned about job loss. Did you know a lot of people have lost their jobs since last March? Apparently there's been a bug going around or something.
And that he’s an all round great guy
Well, OP hasn't given any evidence that he's not, in fact she's said a number of nice things about him. I don't think a man is a thundering arsehole just because he uses his right of veto in an important joint lifestyle choice that he's under no obligation to agree to. You do, but you also think sharing the earning is the same as total abandonment and couldn't give a shit about his consent or feelings, so why should that mean anything?
Never mind, the fact that from the whole tone of OP’s posts, it’s clear that she is lacking confidence. The clues aren’t even subtle - the fact she is talking about ‘allowances’, or how he’s told her she will feel, or that she doesn’t know how to bring the subject up again.
I'll humour you and take the latest fiction, lacking confidence, seriously.
It's not any adult's job to bolster another's confidence by becoming their financial provider against their will. If she's that lacking in it, then working might be good for her. "Allowance" was her word, which she used to indicate her own concerns about what such a setup should mean. She gave no indication that her husband would see it that way. But as it is, he's not the one who wants there to be any situation that involves anything that could be construed as an allowance anyway, so it's a bit of a moot point.
And I'm not surprised she doesn't feel able to bring it up again. By her own account, she's done it numerous times ("he always says") and the guy has made it clear he doesn't want this. How many times are you allowed to pester someone before accepting that this mutual, joint lifestyle choice isn't what they want and you don't have the right to force it on them?