It just seems like it isn't true because of the high rates of divorces and unhappy relationships in the world.
Lack of commitment
lack of education on how to manage a relationship
Lack of putting in the day to day work
Getting encouraged by friends and family to bail on the marriage
Being afraid of needing a person emotionally or economically
Not ever having done the work to know yourself, there for you cant really know someone else
and so on.
My belief is that the Barney version of soul mates is nauseating. But two people who choose to lock their lives together and all through life both refusing to unlock and walk out.....ya, I believe in that. It is not magic, it is shear will and hard work.