In a relationship where you have shared expenses (not just meals out... but stuff for the house and kittens) I think the fairest thing to do is to set up a joint bank account or pot and deposit equal amounts into it every month. Then you can pay for all your housekeeping and meals from there. I don't know how easy that is to do for someone unmarried, but it should be possible in this age!

What I pay when dating depends on our incomes, I think. I'm a student so I don't have very much; if I dated someone who had a big allowance from his parents, I would expect him to pay for more. If they work for their money like I am, the amount of income is irrelevent. Generally, if I don't want to go somewhere, or I am not sure about going somewhere because I don't have much spare cash, and they insist on going, I would like them to pay for me because I wouldn't have gone were it not for them. If we are going out for meals together, I would split the bill and buy them drinks. The next time, maybe split the bill and have them buy me drinks.

It's complicated!