Been married for a good number of years now and we don’t have any method to split expenses. Both earn equally well and this is also a personal preference that works for both of us.
I assume couples with a large difference in pay might need to have something in place. Also mindset matters - for us it is ‘our’ money so in the end doesn’t matter who is spending on what. If I compare the spends in a year, both world almost end up spending equally. What matters is how much we are spending and saving combined.
Just speak to your spouse/partner and figure out a way that will work best for you. Something that has worked for others might not be your best bet.