Gary and I have always had separate bank accounts, and when he retired we re-purposed his into a 100% responsible savings account and mine into a 100% reckless spending account, and we both share both accounts. Of course, we transfer a percentage into the savings account automatically, and when extra money accumulates I shuttle it to savings after a few weeks, because I can't wait around forever for that money to be spent. The grasshopper gets at most a month to spend it, and if he doesn't, then the ant takes over.
It has worked out well, after a disastrous early start in which I tried to get him to economize. If you look at his actions it seems that he's fine with the arrangement: he spends money on me, he spends money on his parents, he spends lots of money on raccoon food, but only on rare occasions will he spend money on himself. Recently he bought his father a muffler he admired, and I couldn't get him to buy one for himself. "Spend your money on yourself for once!" I will say.
It's frustrating, because he will say, "Well, it's not my money, it's your money."
I always counter this with the same argument: We can spend at least a mortgage payment on him per month because he spent years paying off our mortgage. We can spend a car payment on him because he doesn't want to buy a new car for his ego. We can spend the extra money he saved up for retirement because he isn't taking social security.
The second argument, which I never get to, is: if it's my money, why does he think I'd have a problem spending it on him? Does he think that I'm too stingy for him to have new shoes, but that I'd prefer that our gold is alchemized into raccoon poop?
I got his iPad while he was asleep and bought him that muffler.