Hi, Eliza,
Welcome to SR! No clue about your guy. Couple of possibilities--he just didn't feel a "click" with your (happens to everybody), or maybe he's just not ready for a relationship--got cold feet or whatever.
I wouldn't make too much of it. You've only gone out a couple of times. I've had the exact same experience as you with plenty of non-alcoholics. Sometimes things just don't work out.