A person's dreams, their good intentions, their ideas, their potential--all that is a part of who they are inside. But their habits, their discipline or lack thereof, their integrity, their reliability--those are the part of them that will affect you more over time.
This is a big part of why I'm against dating anyone you haven't known for some months as a friend. While you're caught up in your hopes of who they might become for you, and while both of you are caught up in impression management, you just don't have a chance of getting accurate impressions of each other. I've got an article on this, in case you're interested.
But I hate it that you lost a year loving someone who gave so little back to you.