Am I Not Taking a Hint?

I had one of the most romantic experiences of my life when I met this guy two years ago while we were both studying abroad. We both really liked each other but were so in-the-moment we never talked about taking it further and knew that the relationship would end once the semester was over - we live very far apart from one another. The problem is, I'm still infatuated with him. We've communicated sporadically - about once a month in these last two years - just as friends because both he and I have been in casual relationships - most of the time I'm the one to initiate it - he responds SOMETIMES and says things like "I miss you" etc. I write him because we just have such a good chemistry - close to being a soul mate. I know this isn't going anywhere anytime soon so should I take his poor communication attempts as a hint to give it up or keep writing (it makes me feel better)? I want to remain friends and keep in touch with him (I admit - hope we meet again one day).