Hmmm, it depends how grown up you wanna be. You might earn the same salary, but your lifestyles will be different. You dont say whose house it is. If it was my house and she was just living there, i would just ask her to give me a little towards the bills and let her keep the rest for herself. But if you wanna be childish and split everything 50/50, where would it end? would you make him pay the day after for a takeaway which you bought the day before? Would you still pay half the phone bill if it was him on the landline all the time and you on your mobile? would you expect him to pay half your mobile phone bill cos you were texting a lot more. What about the internet bill? if he never used it, would you expect him to pay for half the toatl bill?i could go on all day, but had better not. Basically, what i am saying is, you have to come to some sort of agreement as to who pays what and how much towards. there could never be a 50/50 split. It would end up causing too many arguments...