I think the original question is whether anyone has lived with their intended spouse prior to marriage rather than have you lived in a house with a person of the opposite sex.
This is one of the great divides between east and west.
In the east and in Islam, living together without marriage is forbidden and thats fine.
In the west, it is frowned upon (usually) but not strictly forbidden, even I think in christianity or judaism but not entirely sure about that. Even parents will accept a living-together arrangement in the hope that their child will find happiness.
The feeling in the west can tend to be more about finding the right partner, giving life together a try before taking the drastic step of marriage - which is a promise to spend the rest of your life together. It typically isnt all about wild sex and lack of morals.
To each his own yeah? No one can say eastern culture is better or western is better....they are DIFFERENT, with different rules and values. A westerner cannot really be expected to fully understand the concept of arranged marriages and separation of sexes and easterners cannot be expected to fully understand living together and love marriages because its so very different. But either one is ok within their own culture based on the morals and values that the parents provide - there are good people and bad people, good intentions and bad on both sides yeah?
Then what is the reason behind living under same roof. All things they can find out without living under same roof.
I won't like to see the person before marriage and ewww I can't think about living under same roof even for few minutes. Thats I will call nasty.