There is no such thing as filing for separation in Virginia. In Virginia separation begins when one party forms the intent to separate from their spouse and then they must carry that intention out for the statutorily prescribed time. Even if your spouse does not want a divorce or to separate, it does not matter if you have formed that intent.
The Court will generally look at behavior and actions to determine when the separation occurred. The easiest way to separate is that one party moves out of the shared residence. This creates a clear cut date that you and your spouse separated. However, oftentimes parties are not able to afford two residences and often live in the shared residence together even after they have separated.
If you are going to reside in a shared residence with your spouse after you have separated, then you will need to take steps to ensure the date of separation and that the Court will recognize the separation. Generally speaking you and your spouse would need to be sleeping in separate bedrooms, not engaging in a sexual relationship and not holding yourself out as a married couple.
You and your spouse will need to essentially live as roommates and that is it. It is always good to have a conversation in writing with your spouse, either text or email, verifying the separation and how the two of you will carry forward with things such as expenses, etc. while still living in the shared residence.