If you meet your ex-boyfriend today, he sees you, your team, and even turns away a few seconds later. He didn't say hello to you because he thought he had broken up with you and there was no need to contact you again. Just be the most familiar stranger, there is no need to say hello to each other to increase each other's troubles. So I think that's what he thinks, so he doesn't even want to say hello to you, which shows that he actually wants to break up with you completely.