I found the article Is God going to hook me up online? Assessing Christian Mingle and ‘soul mates’ interesting, mainly for the discussion of ‘soul mates’. Although the article is examining religious perspectives on ‘soul mates’, I think the concept transcends religion.
The article points out that one problem with the ‘soul mates’ concept occurs when people believe that finding their soul mate will result in an easy, blissful relationship. When relationship problems arise, as they inevitably do, people with this perspective can be quick to decide that it means that their partner is not their soul mate. This makes maintaining a long-term relationship difficult.
On the other hand, the article presents this perspective on soul mates, attributed to the Jewish Kabbalistic tradition:
If a partner is helping you overcome your negative traits and negative challenges while helping you pursue your positive traits, that person is your soul mate, says [Rabbi DovBer] Pinson.
This definition of soul mates opens up some very different possibilities. For example, if you find it difficult to be patient and your partner does certain things slowly, the fact that s/he is presenting you with an opportunity to develop more patience could actually indicate that s/he is your soul mate. This is very different from the idea of a soul mate as the bringer of effortless bliss.