Problems with an ex-boyfriend

So, I'm having a really hard time handing my ex-boyfriend.

Here's the story: I broke up with him August 2014. I did it for a very good reason, because he was getting very emotionally abusive, giving me ultimatums, being really touchy and controlling with who I hung out with, just plain awful in general. I don't know how I ended up sticking with him for four whole years. I think it had something to do with my need to not be alone. I also broke up with him because we had very different life goals that conflicted.

Anyway, I was with him for three of those years but then the relationship turned long distance because he is originally from another country (he was an international student at my university) and had to return. We tried to continue our relationship via Skype , but the problems with us actually began way before he even left, I was just too afraid to bring them to the table.

When I finally did and broke up with him (after several failed attempts and anxiety attacks) it was a disaster. He took it extremely hard and got so upset he apparently ended up in the hospital and was on a type of suicide watch. I felt terrible, guilty. I didn't want him to die. I was so afraid that something bad would happen to him. So instead of just breaking off the connection with him completely (as it had been suggested by several friends and two different counselors), I decided to tell him that we could still be friends and talk. At first he was trying to get me back as a girlfriend, but these days I am at least glad that he's realizing that he doesn't have a chance with me anymore.

The problem is : he is still being extremely clingy when I talk to him online. See, when our relationship was long distance, we would talk on Skype every day. Literally I would come back from class and get on to talk to him, morning and night. It was a constant thing pretty much. Well now, I don't talk to him through skype, but through Facebook chat. I also am unable to get online much because I am just too busy.

He just does not understand that! If he sees me on Facebook just to check something for like five minutes, he jumps down me in email saying things like "Why didn't you say hello to me?" or "Is it too much to talk to me?" Even though I had a conversation with him the previous day. If I go a few days without speaking to him he gets all over dramatic and says how much he wants to die because I'm not apparently paying enough attention to him.

I don't know what to do! Part of me just wants to end all connections with him but another part of me is afraid that if I do, something terrible will happen to him and he might hurt himself. Also, another part of me doesn't want to stop talking to him because I still consider him a friend. But he's making it difficult for me to even be his friend by his whiny, clingy, and just overall overbearing attitude. Has anyone been in a similar situation? Do you think I really should just end all connection? I've tried telling him over and over again that i can't always talk to him 24/7 but he's not getting it. He wants us to talk as we were talking when we were together but it's just not going to happen anymore. Ah, I'm so stuck...