My girlfriend (24F) and I (29M) have been dating for 2+ years and are now living together in London. I've been working for a few years now while she has just graduated, and recently received a job offer in a city 2 hours away.

Since her work requires her to be in office at least some days a week (could be anywhere from 1 day to 3 days or even the whole week), she has decided it's best that she rent an apartment in the new city. My work is also semi-remote (2-3 days in office) and we have decided that we will move to an apartment near the train station where she needs to commute to/from in London, to serve both our needs.

The expectation is that she will live in the new city for the days that she needs to be in office (but with uncertainty about how many days per week, as mentioned above), and commute back to London the other days. If there are weeks that she is busy or unwilling to, I don't mind making the commute, but I do expect that most of the time she would be doing so since our current city is MUCH bigger and all our friends are here, etc. Also, I work pretty long hours (between 11-14 hours a day), whereas her new job is expected to be 40 hours a week (8 hours a day), so realistically it will be more difficult for me to travel anywhere on weekday nights.

Because now we need to rent two places (one in each city), I proposed that we sum the rent for both places and divide the sum evenly. Likewise, for commute travel expenses, we can also divide evenly regardless of which one of us is travelling.

She disagrees and proposes that she only pays for the rent in the new city. Because the new city is significantly cheaper and because she is only staying for part of the week, she is looking for shared accommodation that ends up being only about half the cost (£800) of what a rental for a studio or 1BR costs (~£1500) in London near the train station. I think it's grossly unfair that by her proposal, I will essentially be paying twice as much rent as she would be; she counters that I could get a cheaper shared accommodation, but both of us have lived by ourselves (even before meeting each other) for much of our adult lives, and sharing is not an option I am willing to consider in my late-20.

She also says that she is carrying more of the burden of commuting, but I point out that it's much more natural for us to spend weekends in London (for reasons listed above). In any case, I did propose that we split travel costs evenly so other than the time spent travelling, monetary costs don't matter regardless of who travels.

For context, I do earn significantly more than her and this is my 3rd year working. We live together and currently split our current rent evenly (about £1000 each); she was previously living off an allowance from her parents. I pay more for bills and living expenses since I earn more. It feels to me like the status quo is exactly what I proposed, whereas her proposal drastically shifts the weight of payments to me.

I should also add that I don't take any money from my parents, whereas she often gets supplementary allowance from her parents for travels or shopping. She claims this is irrelevant because it is none of my business how her parents dote on her, but while that is true I do think it should factor into consideration when we decide the split of payments.

We've reached a bit of an impasse on the issue and would appreciate some advice.

Tl;dr, girlfriend got a job 2 hours away, and we probably need to get two apartments, one in each city. I proposed splitting the sum of the cost of both rents (we currently live together and split rent), but she proposed paying for one each (her new city is much cheaper than London where we are now so I think this is unfair).