I think, for a modern world of equality, households should just be separate. Married homes should be essentially duplex setups so that each person can secure themselves in their own private spaces.

For a number of reasons, not only is safer for any potentially abused partner, but gives couples a pre built separation. Though, while some may argue this is "half foot in the door" idea, I also think it is healthier for people to have some degree of separation and privacy, at least the ability to get it in short notice.

Also, times are different. Relationships are less long lasting, mostly due to lowering social pressures and resources for abuse victims. I think designing housing more towards couples specially is a good idea, but reality may obviously disagree.