Me and my sister live together and split some of the household tasks. Basically, we have a deal on cooking, we each have set days that we cook for each other and every time whoever didn't do the cooking, does the dishes. That works pretty well except for the days my sister spends with her gf. She generally arranges it for days when I would be cooking anyway, so I don't miss out. The Only problem is who should do the dishes on those days, I think she should, but she is...not so keen, obviously.

Am I the asshole?