A soul mate is another person that connect to your soul on the same level. Now many people say that only one person can be your soul mate but that is not true. Just like you can have multiple best friends, you can have multiple soul mates. Soul mates do not even have to mean a husband, wife, boyfriend or girlfriend. It can just be a soul that meets your soul in life and just betters you. That to me is what a soul mate is.
My perspective of a 'soul mate' is that is the one person who, as soon as you meet them, you feel a connection; Like you know them or like you've met them before when, really, that is the first time you ever seen them... :)