Anyone dealt with an ex purposefully bringing other girls around you?

I (21F) was dating a coworker (26M) for a couple months, (I know terrible idea, but I was really infatuated with him.) we both work at a bar and broke up about 2 months ago primarily because of his emotional unavailability. We’ve been able to stay very civil and friendly at work but the problem is he’s started to bring random girls to the bar on his days off that he knows I always work, they sit at my bar (1/3 choices in the venue,) and he acts like he doesn’t really know me. I’m not even very upset that he’s seeing other girls, just that he feels the need to so blatantly rub my nose in it.

I don’t know how to deal with it, half of me wants to make it obvious how annoying I find this, the other half wants to act like I don’t care at all so as not to give him the satisfaction. I have a hard time understanding why he would even do that? He was the one to end it with me, it’s not like I hurt him and now he wants revenge, the whole thing just feels very cruel.