Sure, it can be exhausting to keep track of everything separately and constantly re-calculate shared bills each month. But it doesn't have to be split like that. Here's a few examples I've seen that seem to work well.
Example #1: (a married couple, with equivalent incomes)
Add up rough costs once (water bill, electric, cell phone, rent or mortgages, etc), just one time. Then both commit to automatically dump maybe 5% more than half of that every month after. (So if all monthly costs add up to say, $2800/month, each person puts $1500/month into that checking account). Bills auto-pay automatically, the balance should slowly grow, if it starts to go too low, recalc to make up the difference. (kind of like how escrow works on a mortgage)
Example #2: (a married couple, with wildly different incomes)
Have a discussion about shared goals and shared debt. (Is the poorer spouse still paying off student loans? Is the wealthier spouse paying off debt from a previous marriage). Figure out a number that feels 'fair', based on cost of living and divided by share of income. And then the poorer spouse contributes this 'fair' fixed figure per month automatically, and the wealthier spouse covers the bulk of everything else. For example, if Person A makes $110k/yr, and Person B makes $40k/yr, Person B might contribute a 'fair' 50% of their take-home salary (~$1300/month) and Person A might contribute a 'fair' 50% of their take-home salary (~$3300/month) and all shared CoL expenses come out of that combined monthly pot (Groceries, Utilities, Rent+Mortgage, Car Payments + Insurance, Cell Phones, etc)
--
> And then you have those cases where I can afford to go to Disney World, but my spouse only has enough for Six Flags because she makes less or hasn't been saving--now what?
You just decide what it's worth and why, and make an agreement on how to save for it? I think your assuming the talk is exhausting because it feels like a constant fight or at least a negotiation and a math problem. But if set it up right, you only have them a couple of times a year, and if you are doing these conversations with someone you love (presumably, someone you love enough to commit to marrying them), they don't have to be that exhaustive, it's just fun banter, the way a couple might playfully banter about what to eat for dinner, or what movie to go see or such.
> OMG that just sounds like so much work to manage, all for what?
Some people have put their 110% effort into a marriage for many years (or even decades!) only for it to end in disaster anyway. You can fully commit to a marriage, and also think people can change over time. It's loving to help people feel safe and secure, even from someone who might be your own partner. Especially for folks who've gone through a divorce already, safety and security in any possible scenario (even the worst one) can feel very loving too.
It only takes one time of being "committed fully to marriage" and having it end in divorce anyway, before you realize it's crazy to pretend that's never a possibility.