Wow, this is a great topic...and I can't seem to figure out what side I am on. I am married (going on seven years(wow)). But I am also much more frugal. If it were up to me, I'd eat tuna and tap water if it meant I didn't have to work. We also have a daughter, who my wife loves o buy things for. But I also just spent my tax return on a truck, despite the money was ear marked for debt. I could have gotten another very cheap beater, but getting sick of fixing and borrowing.
One one hand, I know friends who keep things separate, and I know it shouldn't because it's 2013 but it feels strange to me. Maybe i am a little traditional in the sense that you should be actively working together for similar goals, Keeping things separate and having separate goals seems like an easy way to split. I also thought about what if we did that, I make MUCH more then SO, and I'm great at hustling up cash. What happens when I retire at 40 and she's working, just point and laugh and say haha? I'd end up subsidizing her then. maybe. Who knows.
The way we do it is that I do it. I've learned with my SO that data is better ammo for an argument then logic, so When I said we can't spend more then XXX a month and we spent more, I showed her. We fixed it. After about 18 months of trying different systems, and different ideas, we landed on a $200/week CASH payment. This covers, food, gas, coffee or what ever else we "need" but once we're out we're out till Sunday. The 200/wk is enough where I can pay all of the other bills, debt, and still save. Meanwhile she is much more aware of what she spends since she knows it will run out, but its a short period of time so if it does, she only has to make it a few days.
She trusts me when i spend, save, and a lot. I've bought two rental properties, leveraged, and started a new business last year.
Sometimes I think it would be nice to say, you live your way and I live mine. And I'll just smile when you leave for work and I'm enjoying a beer at 8 am on a hammock...but then realize that wouldn't be fun at all, most days anyway.