Personally, I have a difficult time believing anything without some sort of proof, and so I have difficulty accepting any of the various ideas about soul mates as true. I think it's important to say that I am not denying the validity of these beliefs (for all I know we could only be half of a whole, destined to search for completeness). I'm just saying that I do not claim to know things which I have absolutely no evidence of other than my own faith. So I do see the different views of soul mates as fantasy.
I definitely do not believe that each soul has a perfect relationship waiting in the wings. I think anyone who has ever been in any kind of relationship knows that perfection does not exist. Every relationship takes at least some work because none of us are perfect. We are only human, as the saying goes. And I believe that because we are human we strive for closeness. I am more inclined to think that that is the reason why people search for someone to share their life with- because humans are social and need companionship.
Our culture is fond of the idea of soul mates. Many very popular books and movies today deal with the concept of two people "completing one another." Concerning Wuthering Heights, I hardly know what to make of those twisted relationships. But if I did believe in soul mates, I would say that Heathcliff and Catherine were meant for eachother.