You can never choose to meet a Twin Flame and the events that unfold after your initial encounter are all beyond your control. You can meet a Twin Flame when you are both single but not ready to confront your feelings for each other which can cause a temporary separation. One of the reasons why a Twin Flame would choose to marry someone else over you is because they could be afraid of feeling vulnerable when they are around you. It is not your fault.
A Twin Flame would deny themselves the blessings of a union with you because he or she does not feel worthy of pure love. It could be that the overwhelming feelings they have for you trigger so much pain within themselves that they had buried within themselves. Not every Twin Flame is ready to confront the chaotic Twin Flame emotions.
Not everyone that has met a Twin Flame is willing to change their life situation to pursue a union. The changes that we Twin Flames go through are accelerated, unexpected, and not in our power to control the nature of the process of change. A Twin Flame would therefore choose to run into marriage with someone else because it feels easier and safe.
Fearing the changes & uncertainty when you meet a Twin Flame, it is not always roses and peaches. You go through excruciating chaotic emotions. Your dreams change. Your emotional well-being is destabilized. You go through a series of energetic cleansing. You are forced to make a change to align yourself with the new Twin Flame shared energy.
When I was new to the Twin Flame experiences, I did not admit that I was a Twin Flame. I did not want to go through scary experiences. Societal pressure some Twin Flames are forced to marry someone else because of the pressure from family and friends. In cases of arranged marriages, you cannot intervene if your Twin Flame family has the power to choose. The wrong match for relationships even though you share a bond with your Twin Flame, it is not a guarantee that you are a perfect match for a relationship.