The way I look at it, is not everything is meant to be, but these feelings are real. Maybe it's a chance to make up for mistakes you made, or a missed chance.
If either of you are already with someone, then you need to be friends, and nothing more. But if you're both single, there's nothing wrong with exploring these feelings.
Either way, it's going to be just about impossible to keep out of each other's lives. It's a matter of what you want that connection to be.