Guy wants to "cool it"?

I started talking to a guy at work, and we were never particularly flirty. One night when leaving a bar where as a group we were drinking, he got my number to ensure I made it home safely. This lead to us developing a fairly strong friendship and flirtation through text messaging that carried over into work. We began seeing each other, and eventually sleeping together, for about three weeks during which he held my hand when out at bars, made me breakfast in bed, and would text me every night. He even asked that I not see other people. Neither of us particularly wanted our coworkers to find out, though I do not view this job as my future career while he does. One of our coworkers did, and while I simply denied any crush or anything and said he was simply flirty, he freaked out. I sent him a message asking if we could hang out, and he pulled the not mixing work with pleasure line on me. We bickered back and forth, and he said he simply wanted to cool it for a while, that we could still kick it, and he owes me a six pack of beer. I attempted to flirt a bit when talking about how I could cool it off quickly because an obnoxious ex of mine has reappeared, and he simply responded with, "Of course. You're awesome ;)" What is this guy thinking? Do I even stand a chance of it starting again?