For those unfamiliar with the Flashpoint storyline, Barry Allen wakes up in a drastically-different version of the main DC timeline, and one of the biggest changes is that Bruce Wayne was the one killed in Crime Alley that night, and it was Thomas Wayne who became Batman instead, while Martha Wayne fell into madness and became The Joker.
Assuming this information is legitimate, then it’s possible that Flashpoint could be Ben Affleck’s final Batman appearance.
At the end of the story, after Barry had managed to revert the timeline back to “normal,” he visited Bruce in the Batcave and delivered a letter that Thomas had written for him.
If that’s the case, it would certainly make for one hell of an exit.