There’s a Reason He’s an Ex
I once had an ex who refused to accept our breakup. He saw me at a bar with some other guy and tried to tell my date he was still my boyfriend.
I tried to explain that we were broken up, but the date was pretty much ruined once my ex showed up, sloppy drunk and screaming about how I was cheating on him in front of his face. There’s not much you can do to really salvage a date under those circumstance.