Sometimes we get so caught up with planning out the future that we forget about what we have now. It's usually the things closest to us that we tend to overlook, and that's when it becomes a thing of the past.
I used to believe that if you really loved whoever you were with, you wouldn't break up or take a break because it's bs if you do. If it's "true" love, you'd stick it out. But the world likes to screw around and things don't pan out like how you always want it to. In fact, it usually never does. Cookie cutter ideals don't translate in reality.
In relationships, some people grow together--for others, they grow apart. I don't mean in feelings necessarily, but in the sense that they need to grow on their own. Sometimes, when you grow on your own, you need to do it alone to figure out where you are and where you want to be in life in order to have a sense of self. And then maybe when you do--when you build your own foundation to stand on--you can truly be with another person and stand together.
In the meantime, fondly remember them (but don't dwell in your memories) and move forward--maybe you'll run into them somewhere down the road. And if you're still thinking about her/him and s/he is still thinking about you then, take a chance and try again.
In the end, if you were meant to be, maybe it doesn't really matter how things work out--just that they do.
If you're wondering, yes, I am still happily in a relationship.