Money Relationship Issues with girlfriend

I feel like I'm missing a key part of the story here, but shall wade in with my opinion anyway!

If divvying up how to cover additional and unexpected costs or "treats" such as dinners out and holidays is being problematic, then I'd suggest increasing the amount you both put into the joint account (perhaps in proportion to your income as you currently do) and use that money to cover ALL the costs that you incur as a couple including dinners out, groceries, car servicing (if a shared car) and also to set up a shared savings account for unexpected expenses such as a new boiler, or treats such as holiday savings. Then the money you each have left over in your personal accounts is for all of your own expenses, such as clothing, drinks/meals out with friends, train/tube to work, visiting friends and family without boyfriend/girlfriend. I don't really understand the whole trying to keep a tally of who pays for what and when - just use a joint account for everything and work out how to fund the account!

Edited to add: and communication is key. If you can't talk honestly and openly about this issue now and find a mutually agreeable solution then frankly you're storing up a lot of potential future issues!