We had to do a 'preparation for marriage' course!
It was quite intense, over a weekend, but one thing that came out of it was the importance of being on the same page financially- even if that meant both of you were a bit profligate!
Also, in that particular country, after living together as if married for two years, legally you gained the same rights and responsibilities as if you were married; which is not the case here in the U.K.
I think the idea that after paying either equally or better, proportionally into shared household bills, each individual's cash is their own- is commendable, til one party (the woman 95% of the time) stops work to raise DC, then goes back PT in a more junior role.
What happens then? I'd be wanting to know before getting married, let alone before having DC!
FTR DH and I have no private, let alone 'secret' savings. Everything goes into a joint account that we both have equal access to. If things have to be in singular names, like ISAa we both know exactly how much is in each other's.
He is the higher earner (£65k); I'm PT on £30k; I took 5 years off work for the DC and have been PT ever since. And it would piss me off greatly if I was financially disadvantaged because of it! We're a partnership.