First of all, where does this attachment issue stem from? It's slightly worrying. If you can't figure out why he's like this, its best to keep distance. Realistically, the way he's acting will progressively grow into some kind of form of mental/verbal abuse(?). I wouldn't know since you can't judge without witnessing it, but this perspective makes it seem as if he's trying to induce some kind of guilty conscience on you.

Honestly, just take some precautions. I wouldn't know him well enough to see if he's the type to stalk or threaten suicide if he gets to the brink of desperation, but from what I'm reading, his affection does show some worrying signs. Be careful : /