The very idea of a "soulmate" is sophomoric nonsense that leads millions, especially women, into awful marriages. If you are looking for that perfect someone, you are too immature to get married. This is the real reason why there are so many cohabiting couples; they have found someone who is OK, but still looking for THE ONE.
Imagine you live in a culture where arranged marriages are the rule. Your parents find someone for you who is mature, of good character, comes from a good family, and has no significant flaws. You and that person know that marriage is a lifetime thing (in that culture), so you go into it trying to make the best of it. You treat the person with kindness, consideration, and dignity, and they do the same with you.
Bingo. You have a good marriage. As time goes by you learn to "love" that person, meaning you feel an emotional attachment that is the most intense you are able to feel.
Alternatively, after years of looking you find your "soulmate." Shortly thereafter you get married. That intense level of emotional commitment fades, the person gets fat, sloppy, irritable. They pay more attention to the kids, the job, the neighborhood, their parents than you think appropriate...more than they pay to you, actually. You never thought of marriage as a mutual commitment. You thought of it as an opportunity to live blissfully for the rest of your days. What happens when the bliss fades away?
Stay single. Do the world a favor.