I recently talked to a friend who told me that she was visiting her conservative religious family for a birthday and brought her partner for the weekend. Over the few days they slept in separate rooms.
The question that immediately came to mind was 'why?' Who was it that didn't think they shared a bed back home?
It couldn't be for the parents or siblings because they were perfectly aware that my friend was an adult with her own home and in a long term relationship. And it was unlikely an act designed to protect God from the knowledge for the parents believe in an omniscient being. This was not then a direct act of deception to keep the knowledge from their family (we don't sleep together) but a pretense (lets all pretend we don't sleep together).
What we see here in action is what Lacan called the instantiation of the 'Big Other'. The Big Other is a virtual reality (see this post for a description of the virtual) that is not actually believed in, but which informs our actions none-the-less (not existing, but insisting). The Big Other, in the example above, functioned as a non-existent subject that was oblivious to what was going on, a subject who the whole family had to keep in the dark about the facts.
In this way the Big Other prevented an unpleasant confrontation in the family. It was not that an antagonism within the family did not exist, but rather that everyone was acting as if it did not exist. By doing this a certain level of superficial relationship was able to be sustained (which suited my friend, who didn't want some big argument).
Had people been confronted with what they already know then the obvious differences that exist concerning attitudes toward religion, sex and morality would have been brought to the light of day. While this can no doubt be traumatic it is also what is necessary in the journey towards healthy conflict, deeper discusion and ultimately healthier relationships.