Him bringing up having children may have been him guessing at what you might want.
Unfortunately, whatever he is dealing with, he is unable to maintain a relationship. This might be related to alcoholism, it might not. There may be other issues he has that he chooses not to deal with directly, which is, of course, his choice.
Yes, if you were looking for a relationship to progress this certainly wasn't it and of course there was nothing wrong with bringing that up. The fact that he took offense to that, rather than discussing, again signals a problem.
Do you think maybe, somewhere in the back of your mind, as much as you are hurt and perhaps missing him right now, that this was the wrong relationship for you?
What do you want in a relationship?