Ford just invented a bed that stops one person from hogging too much space. The bed has sensors in it that detect where both people are sleeping.
And if one person crosses the 50% mark, the mattress gently moves on a conveyer belt to give the other person more space back on their side.
Unfortunately, they just made the bed as part of a promotion for the lane assist feature in their cars. But maybe if enough people DEMAND this from a bed, it can become a real thing.