Yuck, that sleeping arrangement sounds hideous. I hope it is temporary because of your living situation and that you normally have a fairer system than operating out of his whims.
It is important, I think for anyone in a polyamorous relationship to be very clear about what they want to achieve. It sounds to me as if you are currently a secondary and you really want to be at least a primary (if not monogamous).
I am a mono in a poly relationship but I am very primary. Z loves his other very much but we are committed to living the rest of our lives together (if we can maintain the quality of relationship that long). I know I always come first because our lives are so meshed. That was what I wanted in a relationship (among other things). I see the poly bits as just stuff I'm growing through.
I wish you clarity.