It is easy to turn a friendship into a relationship but when the relationship fails, you lose both - a friend and an ex-boy/girlfriend.
I know, my opinion might be biased but that's my life experience. Why do I brought this thing up? When one of my relationships ended, my ex told me, "we can still be friends", "keep in touch" and of course, knowing that your failed relationship didn't hold any grudges on both sides, it is consider a win-win situation for both. But then of course, we never keep in touch and basically we are a total strangers to each other soon after that... until one day, "have u ever thought of me?" came.
What? Out of the blue? Hmmm... honestly no! No matter how long I had known you, once you treated me like a stranger, YOU ARE a stranger to me. I'm not a hypocrites that I would smile and try to make you feel better by saying that "yes, I have thought of you". For me, you are my forgotten past... remember you? Might be on a spur of moment but that's it.
Living on the past won't get you anywhere.. living your life presently might get you somewhere and living forward will eventually get you somewhere...