I don't want to hurt him

I used to date this guy a long time ago. I ended it because I felt as if we  didint have a romantic connection. I didint just loose my boyfriend, but I lost a VERY good friend. However now 3 years later we're taking again.  I've been going through a rough time and he makes it better. I don't want to stop taking to him. However I feel as if I'm hurting him. I don't know how he feels, and if he still has feelings then I'm just giving him the wrong idea and hurting him yet again. I just want to be friends. Do I need to stop talking to him or what can I say to him to nicely imply that I need him as a friend but I'm not I retested in anything else? Or should I just drop it?