I don't believe there is only one soul mate out there for each person. It's all too random and there are far too many people in the world to think there is one single person meant for me.
I love my DH with all my heart, and I think we make a great match. My feelings are no reflection on our relationship. But if something (God forbid) were to happen to him, I truly believe I could find someone else who I would be just as compatible with, and love just as much. And I think he could do the same (and I would want him to).