New job, old flame.

I started a new job this September. I am a teacher but I didn't start until the first day of school so I hadn't an opportunity to meet my new coworkers. Yesterday, while in the teachers lounge, a teaching assistant I hadn't seen before walked in and said he needed to call his sons school to make sure he got there okay. As he was on the phone he said his name which I immediately recognized as the name of someone I "dated" 10 years ago. I was so shocked. I didn't say anything. To be clear, we didn't "date". We "talked" for a couple weeks then went on two dates but we were both in a pretty bad place in our lives and looking for validation so it went pretty far if you know what I mean. I looked up at the wall and there was a board that said "welcome new teachers" and two of the names were ours. Later that day, he came into my classroom with his class (I teach a special). He stayed for about half of the class time then escorted a rambunctious student back to their room. Anyway, neither of us said anything. It wasn't the time or the place, plus I don't think he even recognized me. Considering we now work together, I don't know if this is something I should bring up especially since I'm not sure if he even remembers me.