What's a "soul mate"?

Last night I picked up, almost at random, a book I’d never heard of (Red Hot and Holy: A Heretic’s Love Story) by an author I’d never heard of (Sera Beak). In chapter four she says the following: 

Spiritual teacher Caroline Myss defines a soul mate not as some sort of perfect Prince (or Princess) Charming who chariots your personal fairy tale into the happily ever after, but as the person or people who annoy you the most, push all your buttons, make you face your shit, and even seemingly “hurt” you (or your ideas of who you are) or screw up your life (or your previously set plans for your life), thereby forcing you to grow in new directions, developing and realizing new aspects of your self (positive and negative) that you probably would not have done without their, er, “help”.

Dear God in Heaven, don’t tell me this means Wife!