My annoying ex

I have this annoying ex (we are still ish-friends) and he wants to date me. Yesterday I got drunk and sent him things accidentally, this was the first time in a while we talked, and I guess he missed talking to me because he won’t leave me alone now. He keeps wanting to talk online and wanting to chat but I’m not into him at all. I don’t want to block him from things and delete him from my life completely because we are still friends but I don’t know how to tell him I’m not interested without actually saying it to him... I don’t want to just say I don’t like you because that’s mean but I don’t want to keep leading him on. Any tips??

UPDATE: I know I have to tell him and I will but I don’t know what to tell him. Like how do I just bring it up in a conversation...