The Flash: 10 Ways Ben Affleck's Batman Could Be Written Out Of The DCEU
6. The Movie Makes It So He Never Actually Existed
Much to the chagrin of many comic book fans, the events of Flashpoint wiped the old DC Universe out of existence. Initially, Barry Allen arrived in that aforementioned war ravaged timeline before creating a brand new one (known as "The New 52" Universe). Certain characters - like Wally West - were no longer part of continuity, while others were changed in significant ways.
If something similar happens in The Flash, then Ben Affleck's story could end as simply as this: he just no longer exists. Barry would have no memories of his actions, and while Batman's adventures would still have happened, the main DC movie continuity would be one where Keaton's Dark Knight has been protecting Gotham City for thirty years.
The Multiverse is a complicated place, but with all the signs pointing to Keaton replacing Batman, Affleck being wiped from this world's history might prove to be inevitable. Other characters and stories are likely to join him (Justice League, for example), but this is an inevitable part of Warner Bros.' plan to essentially reboot the DC Extended Universe in The Flash.