A recent American study concluded that as many as
73 percent of people surveyed say they are “making do” in their
relationship because their true love got away.
It appears people settle for many reasons, including fear of being alone or wanting security and comfort with any other person. 17 percent of respondents said they met their soul
mates when it was too late — after they were already paired-off or
married.
So many respondents freely admitted that they are "making the best of it" with their current partner. The response is "it's better to be with somebody than nobody." It seems that settling into a relationship is more important than the relationship itself.
Most of the respondents said that are content with their relationship, but 46 percent say they’d leave their spouse or partner to be with their true love. However, experts warn that the grass make look greener, but there are no guarantees that a past true love will be unrequited in the end.
A clinical psychologists believe the couples are focusing on what they have–not what might have been–might not be the best idea. Once people make an investment in another person, there are ways of making things better so that is why a majority stay.
Loneliness is the driving force that puts people together, for better or worse.
In LOST, it may help explain why so many "wrong" people wound up with each other. People are still head scratching why Sayid wound up with Shannon when he pined for decades over Nadia in both realms. The same is true for even Sawyer, who wound up with Juliet, instead of the woman who fathered his child. And it would seem by process of elimination, Jack settled for Kate, or vice versa since most people believe Kate was more enamored with Sawyer (physically, mentally and personality wise).
The concept that a vast majority of couples never live with their "soul mates" is a sad commentary on modern society. Perhaps, it is generational as the happiest couple in LOST was Rose and Bernard, who found each other late in their lives.