Most Helpful Guy
It's possible, but both have to be mature enough to handle it. I met a girl when I was 15 and we had a year and a half long relationship and we stayed friends. In fact I'm going to Virginia Beach in two weeks to see my cousin and her, she's married now and lives in Texas but comes home to VA about three times a year.
Most Helpful Girl
If an ex is nice and things just didn't work out, I think it's fine to be friends after. But it sounds like your relationship was not a good one, so it's best to just move on from him entirely.