<prompt> Human: I currently live in a 3 bedroom house with 2 other people they share a room and pay 400utilities per month. Recently Ive been having my SO over about 10 nights per month. With me respectively being over at their place the same amount. My roommates in turn want to talk about adjusting the portion I pay to accommodate an extra person being over. Which I agreed to as long as its fair to everyone. The numbers they gave me were:400 13 utilities about 500 for 2 nightsmonth.400all utilities 800 for 7 nightsmonth.12 rent 12 utilities 700 for 15 nightsmonth.I wanted to get an opinion on whats actually fair for everyone involved. I would also like to add that my SO cleans the kitchen and pitches in for groceries. Lastly I also make the most out of the household, but only by 3000. Edit: to clarify numbers  <response>: With me respectively being over at their place the same amount.Sounds like a wash on utilities to me then.400all utilities 800 for 7 nightsmonthUnless your SO is taking two-hour showers or something, your roommates are trying to rip you off.That said... I can understand them perhaps not being completely happy with an extra roommate 13 of the time, even if it means youre gone 13 of the time. That may be the heart of the issue. 