Twin Flame physical separation can last for as long as the Twin Flame partners are willing to work through their issues and move the obstacles that are in the way of their relationship.
The Twin Flame obstacles can be both external and internal and a reunion happens once both Twin Flames identify their problems.
If you are married and with a complicated life situation, your Twin Flame situation can take longer to solve especially if you have children involved or complicated family ties.
If you are separated by geographical distance between you and your Twin Flame, this can also affect how long your physical separation would last because if you both live on different continents, seeing each other again would mean one of the Twin Flames relocating to a new country or you could both meet each other half-way and move to a new country altogether.
Separating from a Twin Flame physically is excruciating and it brings so much heartache.
But a reunion is inevitable if it is meant to be.