I'm guessing our fling is over...but how can I ask him to know for sure?

Guys are NOT complicated! Us girls make them complicated because we try to read all sorts of things into why guys do or don't do things. If they don't show up, they're not interested...it's simple. He wasn't trying to let you down gently, or not hurt you you...he just didn't want to show up. I think he feels safe sending y texts and talking on the phone, but the real deal is totally different and he's not up for it - literally :-0 Move on, don't bother getting back in touch with him, and find a guy who does want to meet up and does want face to face conversations with you. Good luck!