I think understanding "soulmate" -whether or not it exists - can be understood by looking at the antithesis. I know I've been in a mistake of a relationship where I had found the opposite of a soulmate. The things that made her awful for me are characteristics I used to filter people out until I found my wife.

There's definitely an argument that soulmate don't exist. That anyone can be the one that you want as long as you see it through until you feel indifference. For some people, though, that indifference comes much faster. Trust and respect erode way faster than can be undone.