I'm going to add a middle of the road perspective. We have a joint account and we use a budget to work out what we need to pay in. We use Starling that is easy to tag data in but before this I manually worked out each year what our costs were on:
Bills (Council Tax, Elec,Gas, Water,Broadband, TV Licence, insurance, mortgage), subscriptions we both use like Netflix, groceries, eating out together, entertainment, children's costs (clubs, pocket money, school meals), household costs like cleaner or window cleaner or DiY supplies, garden costs, transport (car fuel, parking MOT, insurance etc), and a sum to go into a linked account to save towards a holiday/unexpected costs.
Then we would split all that lot down the middle, divide by 12, round up to add a buffer and that's what we put in a month. Sometimes it needs to go up, for both of us, to cover inflation.
Our situation is I earn regularly and more than him,as he is a theatre freelancer, but he inherited money to allow him to buy our house and put savings aside so we are equal in terms of savings. I also inherited some money and bought a flat and some of the monthly income from that also goes into the joint account as extra income, alongside child benefit, to honour the fact we don't have a mortgage because he invested in the house we live in. As I work from home I also pay in a working from home allowance into our joint as I use amenities and eat food whilst he works away!
In this way we feel Iike we are equal contributors and the reason for any extra contributions I make are rationalised and would change eh if I sold my flat or worked in an office.
It also means we can save or spend all the rest of our money as we wish...I do both!