"Do you believe in the idea of a soul mate?"
No. No I do not. The idea is completely and utterly ridiculous. What was it again? That there is a single individual out there who completes you in every way possible? The perfect complement, the yin to your yang? The other half of your soul? Please don't make me laugh. The idea of a soul mate isn't just stupid, it's obvious. The statistical probability that there is someone out there from the 6 billion people on this earth that makes a perfect match for you is extremely high. Of course that person exists, so the central question is, can you find them? No. It's impossible. Unless there's some key formula, some ground-breaking algorithm that can find you your perfect soul mate, the dream of finding that special someone should remain in the pipe from whence it came from. Is this a cynical view of the world of love? I don't think so.
If you reject the premise of the soul mate, what are we left with instead? Options. That's the key, having the option. Instead of looking for that one ever elusive individual, the ephemeral fairy queen (or king if that's your scene) forever hidden amongst the forest sprites, you will never learn to see past the trees for the forest. I'm not saying that you should settle, but you should look for people for who they really are. Relationships aren't sanguine ships, they're gritty duels and fights to the death. Each victory and loss is as rewarding as the game itself.
One of my favorite songs of all time comes from The Rolling Stones, and it's called "You Can't Always Get What You Want." I love it because it's a simple but universal truth. The chorus doesn't stop there though, it adds a little extra, "but if you try sometimes, well you just might find, you get what neeed." Few creatures are as dumb as humans when it comes to identifying what it is we really need. Animals fucking maul each other for mates, food, and territory -- such a simple life does not extend to us complicated humans. Beneath the veneer of culture, expectations, ideals, and all the garbage that we've collected throughout life, the truth is, we are fucking clueless.
The soul mate is a convenient concept that our brain grasp onto in our attempts to justify our woefully inadequate state of existence. Don't give into the temptation. Don't sit your ass down, waiting for that special someone to come into your life and sweep you off your feet because it will never happen. Then what to do? What is it that we can do if we can't hold on to soul mates? It's easy, you try.