Your going to have fun these next couple of days.

Firstly, don't worry about him killing himself. If he is that unstable, it will happen eventually.

Secondly, don't take him back out of fear of him killing himself. I made that mistake once... Hopefully your smarter than I am.

More than likely, he will cry for a few days and than move on.

You weren't lying when you said he was needy, were you? I'm not insensitive, but for some reason I'm attracted to very unstable girls and have been in your situation (as best as I can tell) several times.