We have separate accounts, had before we married, still have them now. I pay some of the bills, the better half pays others.
For bigger things like holidays, furniture etc we go 50/50. I may get the flights and spending money, she might get transfers, buy all the tickets for stuff we visit etc, buy dinner. It seems to work pretty well.
When I'm looking at cars etc, that's my spare money, I wouldn't even dream of asking her to contribute. Although the other day I did see a lovely series III E Type in Classic and Sports car mag and she did offer, with no prompting, to 'go halves' as an investment!
In very lucky