Separation under the one roof is quite common when family and financial circumstances prevents one party from moving out during the separation period.
If you are living under the same roof as your former spouse, you will be required to prove your separation to the court, which must demonstrate a complete and open break from the marital relationship.
This can include:
No longer having any sexual activity
Living in separate rooms
Not sharing meals together
Not sharing mutual entertainment inside or outside the home
Not sharing bank accounts
Not portraying to family or friends that the marriage is continuing.