We were older and both established in our careers when we got together, over thirty years ago. Over time one or the other has earned more, but we are certainly comfortable. No children together.
DH expected us both just to put everything into a joint account, as he had in his previous marriage. I can't imagine how that works. How do you know whether you can afford something ?
We worked out a budget for all the household expenses including food, bills, and each pay 50% of that cost into the household. Occasional eating out in included. We each do a top up to cover Christmas and holidays.
Anything else we pay for ourselves.
We each very different cars, so pay from our own funds, mine is reliable and had 147k on the clock, his literally turns heads. When we go on holiday together, the household would pay for fuel.
Things like gym membership have moved between household when we both went regularly. I changed it to my account when he no longer wanted to go.
Over thirty years together, never had an argument about money. There is nothing to argue about.
Full disclosure: esp in the early days, I continued my habit from home and s previous relationship of hiding the cost of some extravagant items. He didn't comment either way, until one day he said quietly "I would appreciate it, if you would trust me enough to not lie to me. I have never commented on the cost of anything you buy so feel you might trust me"
Now when I feel tempted to lie about something no matter how trivial. Mostly it's just funny, once or twice it has surfaced something quite important which we have needed to discuss and resolve.
Now I think trust and honestly are very high priorities in a relationship.