What an overrated term. How many times do we hear someone's found their soulmate they get married then a year or two later they are divorced. Not a soulmate. Maybe after a happy 10 or 20 years together you could realize they are your soulmate but they could also be the slob you put up with because you love him anyway even when you clean up after & think better the devil you know.
It is not possible to have more than one soul mate. This is because it is not possible to have equal feelings to different people and that is why one is usually more attracted to one person than the other. The person you have more feeling for is usually the soul make but only if he/she treats you with the same affection.