Keep running into him

So he started dating someone who happens to live close to me. I would run into him daily sometimes 3 times a day. When he’s with her he acts like he doesn’t see me but when he’s alone he stares/flirts which gave me the ick. I started leaving home earlier/later, taking different routes to see if it would stop but it didn’t. Then it got to a point I couldn’t sleep/eat or focus so I packed my stuff and moved to family but the run ins still haven’t stopped. I also keep seeing 11:11/1111 or 444 before a run in.

I would’ve thought that because he’s dating someone else and I’m currently interested in someone else we would be in separation but I’m literally seeing every detail that’s happening in his situation and he’s seeing every detail in mine.

Is this normal? Is anyone going through the same thing? Why is this happening?