I had that opportunity. Someone I dated in my early twenties and when it ended because of mixed signals, we lost touch. He reached out on FB three years ago. We talked about the past and realized that we each thought the other was not invested or interested, though that really wasn't the case at all. We both were in love with eachother, but too unsure of the other's feelings to be upfront and be the first to say it. If you have the chance to speak to the 'one that got away', take it. Even if it does not reignite the relationship, it's good for the heart and soul.