not a useful one.
A lot of people, women mostly, seem to think that a "soulmate" is the perfect person for them, and that if they can just find their soulmate then they'll be happy forever.
From everything I've read (and I must say, the Michael Newton books are incredibly useful and enlightening in my opinion) the entire idea of a soulmate is neither useful nor accurate. We all have souls that we are connected to. We belong to a primary soul group and over the course of many lifetimes we'll have interactions and therefore connections with dozens, hundreds, and even thousands of other souls. Yes, there are some we're far more closely connected to than others. But to think that a soulmate is the one person we're supposed to spend our lives with here, preferably in bliss, is probably not true.
It's my understanding that we are here in this lifetime to fulfill the goals that we set for ourselves before we ever came here. Those goals are probably very complex, and involve the interactions of many others. Some of the people we connect with are here to help us, others are here to challenge us. Over the course of a long lifetime we will have many different goals.
Think back on your lifetime. If you're over even the age of 20, think about how much has changed already. I'm 64. I was married for 25 years, raised two sons, and then my husband met someone he decided he'd rather be with. I often say that it was only after twenty-five years of marriage that he (my now ex) finally met his true soul mate. Yes, I'm still somewhat angry about what happened, but I try very hard instead to focus on what was good during that time, and even more on our two wonderful sons. If I have a "soulmate" it's my best friend Don, a man I worked for nearly ten years with starting back in 1972. We never had a romantic relationship, but I constantly refer to him as my best friend in the entire world. In his life, he's never married. We live about 1500 miles apart, and very rarely see each other. But that does not affect the degree of friendship and affection we have for each other.
Perhaps the experience of a soulmate is highly individual. I don't doubt that for some they meet that perfect persona and life is wonderful forever after. But if we really are here to learn lessons and to grow spiritually (which I firmly believe) then all the trials and tribulations we do experience are all a part of that.