There are plenty of married people who share bank accounts.
If you share a bank account, there is no difference between taking money from the wallet and taking it from the ATM machine. It all comes from the same place in the end. It is no big deal.
In fact if a married couple can agree well enough on money issues to make this work, I think it is significantly better than trying to keep a tit for tat tally of "this is my money and that is yours". Why waste the energy and stress on a bookkeeping issue?
I feel sad for you that you're unable to conceive of this situation working out. It probably sucks to have to squabble about whose money is going to be used to buy toothpaste at the store. I'm glad I don't.
This obviously is not going to work when the couple has serious disagreements about how to spend money. For instance one has a shopping or a gambling problem. But plenty of couples don't have such problems, and for them money really should be a non-issue.
PS I've had a joint bank account with my wife for over 16 years without problems.
PPS My wife knows that she's free to take money from my wallet any time she wants as long as she leaves at least $40 in it. She usually tells me before she does so, but only because she needs to ask me where it is.