I wish I had the perfect answer for you but your situation is more complicated than getting a quick solution. Living with someone means you are in a relationship with them. That relationship makes it very difficult to ignore them. The best suggestion is to consider counseling to explore the dynamic between the both of you that's driving the discord. You will have to decide if living with a selfish person is so disruptive to your life that you will have to make a shift to better self-care and healthier living.