I think, if you are playing hard to get, you do not want to be gotten. When it's the "right" person, things just seem to work.
Maybe "right" means "right now", maybe it means forever, maybe it means for a short or even long time, but whatever is meant to be will be. Each relationship teaches you something, and as each ends, you only get over it when you feel more for the next person than the last. You keep going and growing, and so does your love.
Do not worry about what will or could happen, as long as the other person is legally of age and not a danger to you (ie. don't marry someone who has abused or killed a past lover). Use your heart as your guide, and hope for the best.
What you consider a soul mate is simply someone you love that much, who loves you that much, who fits in your life and whose life you fit.