I think your instict is right, it does seem like he's just not ready to make things permanent. Best thing to do was just talk to him, maybe it's somthing else, if you guys had a great relationship for 2 years then it's really surprising that he would end things so abruptly. Maybe he just didn't feel the way you did, if it doesn't look like he wants to work it out then I think you need to start moving on, or trying to get over him, cuz i'm sure he's already there.
And since you know you cannot see yourself,
so well as by reflection, I, your glass,
will modestly discover to yourself,
that of yourself which you yet know not of.