How to split the bills - not married?

[Soooooooverthisnow]

What is a fair way to split bills here? I would appreciate your views. Together 9 years. Not married. 1DC (6).

I take home £3,800. Partner £1,800.

Mortgage is £1,000 - I am purposely not married and want to keep paying this myself, house is in my name only.

Other bills (utilities, childcare, food etc) c. £1,000 (probably an underestimate)

Car including fuel £200 (ish per month if I average out the annual costs), partner doesn't drive but benefits from me doing all the driving.

I then have about £500 of my own bills (credit card, contact lenses, life insurance, mounjaro jabs etc).

I currently save £500 a month (inc £100 for DC). Partner doesn't save.

I don't know if we should be looking at this proportionate to take home pay, or to be both left with similar amounts each month, before or after savings?

Then how do you split the other things like meals out and holidays?

At the moment I am paying for everything and am skint every month and partner seems to have loads of cash for going out and it's pissing me off. I don't want to approach the subject until I have some options to present. I don't think starting off a conversation with a blank sheet of paper will get us to any kind of agreement.

Thanks in advance

Sorry for being late back to the thread all. I hope you've all had a nice new years day! Thanks for you input and lots to reflect on. Very valid points about commitment and longevity of this relationship. I am not all in as he needs to change his behaviour and seeing him spank £300+ in various pubs over the last 5 days had me seething last night, so whilst I decide if this is a walk away situation I wanted to do something more immediate to redress the imbalance and injustice.

To answer some of the questions I (F) am the higher earner and work term time. Partner (M) works full time. I do indeed do the majority of the domestic tasks and everything else (birthdays, deciding what we are going to eat, DCs classes etc).

He does pay towards big holidays, meals out (because we can't afford to go if he doesn't).

If we separated he'd move back to his mums and continue to spend all of his money every week.

He'd rather spend £££ on going out with friends than contributing to household bills? Paying his share towards a family holiday and some meals out isn't generous if he's not contributing to household bills. Why are you with him? You'd get more money if you split up with him!

Oh god op, after the update and clarification, it'll now be unanimous, this one isn't a keeper. What an absolute child.