In order to obtain a no-fault divorce in Virginia, you do have to be separated for at least one year OR six-months if you have no children and sign a written property settlement agreement. Once the separation period is over, the divorce itself can be done as quickly as within a few weeks, if both parties are cooperative. While it is possible to claim a separation while you are still living in the same home, I recommend against it. It can be difficult to prove and you risk that your divorce will not be granted and you will have to start all over again. Every divorce in Virginia must be corroborated by an independent witness and so it really comes down to how good your witness is about verifying the living situation. If you share one address, the witness must be someone who visits regularly or who lives in the house, such as a roommate, relative, or tenant.
This answer is given in accordance with the laws of Virginia and may not be applicable in any other state. It should not be construed as legal advice, as that would require a more thorough analysis of all of the facts involved in a specific case. If you need further information or assistance, please feel free to contact my office for a consultation.