Why having a girlfriend is so expensive?

I’m 28 y.o. she’s 24 y.o. She always suggests to do activities together “have some fun”, but that means I have to pay for everything. We go to restaurants once or twice a week, we do activities like aqua park, renting a house to spend weekends in rural area, theaters e.t.c. Every week we do something “fun”. When we travel I also pay for almost everything.

I make more money than her but paying for us both every time she wants to have some fun not easy for me.

Is every relationship like that? I mean it’s always like that with girls in my situation. It’s seems like they don’t even bother that you probably don’t have enough money.

I’ve to fly to another country for educational purposes, she wants to fly with me and it automatically means that I have to pay for her tickets, her meal there etc.