It sounds to me that as you say, "she doesn't know anything about loans etc" and would prefer you to do this. That's why she doesn't really get involved or have any interest in it and is happy for you to take the inititative with these kind of things.

On the other hand, it sounds like she doesn't need your advice on domestic things like lunches and where to buy gas - she can do that herself obviously. You telling her that stuff too would be irritating and probably makes her feel like you think she's stupid.

Which then makes her feel like SHE should show an interest or say something in the other matters like the mortgage matters.

Instead of climbing all over every role in the household, maybe you should divide the roles up. You look after mortgages and bills decisions, she looks after the domestic decisions. Lunches, gas etc.

She might drive you nuts for not showing interest in the first place, but you might be drving her nuts too by trying to do everything. That would definitely drive me nuts.

Try sitting down with her and dividing the tasks up so both of you know each other's expectations. And you shouldn't talk about your wife as if she's stupid just because she doesn't understand mortage matters. I'm sure she's not.