Finances are one of those things that should be discussed prior to the wedding date. My wife and I share everything and don't ever question the other's purchases. We have married friends who have separate everything and bicker about who's account certain bills will be paid from!
My wife and I are frugal in some areas and frivolous in others. She likes to buy crafty things, things for the house and clothes for the family, but she doesn't spend much, doesn't demand fancy things and doesn't wear any jewelry, except for her Apple Watch, which I got for her, unasked, a few years ago.
Me? I tend to spend a lot more than she does, on gizmos, doodads and equipment. I like to buy some things in the mid-high tier and keep it forever; she gets that. She also understands that I save us a ton of money buy maintaining our things.
Heck, based on how many hours I work, she's been telling me that I deserve to buy a new WRX STI, if I want to. I think my days of spending that much on a vehicle are long gone, though!
Maybe I'm just lucky, but this doesn't seem like rocket surgery. Buy what you want, so long as it's affordable and justifiable. I think separate accounts for married folks is an absolutely terrible idea!