I had similar experiences with finding people I like online and then communicating all the time. It can indeed be very much like a drug and I had issues with it that were quite similar to my substance addiction - it became a distraction and sometimes had negative consequences (keeping me from dealing with important problems in my life). I felt similar urges with my therapists as well. So, the actual people in this pattern are quite easy to replace. Now I very consciously try to moderate this, even regarding this forum, which can serve a similar role for me if I engage compulsively. Also, I now have mainly one long-term online friend with whom I communicate on almost a daily basis (sometimes we have breaks), but that became a genuine relationship and it feels very secure and truly like a friendship, not drug taking. We actually met on an addiction recovery website and went through phases in the past when the interactions were too obsessive and distracting.