Your story could be my story. I went round and round with my xabf about things like this. The only difference is I don't know if he's ever hit on another woman or cheated. It's really neither here nor there at this point.
Don't beat yourself up for your reaction! I would have done the same thing. Next time it happens, you have the chance to react differently. From my experience continuing getting upset only gives the A the chaos and drama they need. They keep you in their bad place for as long as they can.
They will drive you crazy if you let them! I would try not to give him that power again in the same type of situtation.