A few humble comments...
First, the term 'soul mate' is very difficult to define. Each of us would have a somewhat different perspective, I'm sure.
Now, having said that, let me tell you a tale. About ten years ago, I fell in love with someone I knew was my soul mate. In time, however, she grew weary of me and the relationship came to a close. There were many causes; far too many to discuss here. Suffice it to say, I was heartbroken. Try as I might, I simply could not convince her that we were meant to be together. It was a long time before I could accept what had happened and get on with my life.
Now, some ten years later, she and I are truly incredible friends. Each with our own life, but now able to share them with each other. I have found my true soul mate and she, hers. You see, although I did not consider myself young in life, I see now that I was young in wisdom and perhaps in judgement. Had I known then what I know now, I would have seen that true soul mates would know when they had found each other. There is no questioning, no convincing, involved.
I do empathize with your situation and I wish you all of the best. Perhaps time will reunite the two of you. If not in love, then in life.