No-one can give you a definitive answer.
We split everything 50/50 even though boyfriend earns more. But in our circumstances this means we both have disposable income, and we both save, though he saves more which will go on a joint house. However, I came to the relationship with more savings.
I imagine we will have to re-arrange when we actually buy and costs go up, when I might find myself in your position.
Splitting in proportion to income is something many people do. However if you keep this up, it means if the higher earning partner gets a pay rise, they end up paying more for shared expenses, and the lower earning one less (higher would still have more disposable overall). Do you want to change the arrangement every time one of you earns more? Should you benefit if he earns more?
Or you can have a fixed amount each, and pool the rest, but it sounds like you're not sharing finances entirely.
Not clear if you're considering other shared costs too. Could split rent unevenly, but all other things such as food and utilities evenly.