Two days ago, it was announced, to everyone's surprise, that Ben Affleck would return as Bruce Wayne/Batman alongside fellow "Bat alumni" Michael Keaton in the upcoming film The Flash (See the announcement here). That film will feature Ezra Miller's Barry Allen (Who made his debut in 2017's Justice League after making a cameo in 2016's Batman v Superman) experiencing a cinematic version of the popular "Flashpoint" comic book arc. This saw Barry Allen go back in time to save his mother from being murdered, but in the process sending a shockwave that ripples through history and changes everything in the present. This is what will allow multiple Batman iterations to be in the same film (With both Affleck and Keaton promised to have substantial roles in the film).
However, with this announcement, everyone has been wondering where this leaves Matt Reeves' The Batman, which will see Robert Pattinson play a more youthful (And tactical) version of the Caped Crusader. Some theorized that The Flash will allow, essentially, Affleck's Batman to be replaced by Pattison's version. However, today at the Multiverse 101 panel at the ongoing DC FanDome, DC Films president Walter Hamada reveals that The Batman won't have any connections with the DCEU continuity that Affleck's Batman (Along with Gadot's Wonder Woman, Momoa's Aquaman, Cavill's Superman, and Miller's Flash) is apart of. Hence, Pattinson's version of the character doesn't replace Affleck's older iteration of the same DC hero. Rather, it will be a separate universe altogether with a more grounded take compared to what fans have seen thus far in the DCEU.
The Multiverse has been used by DC/WB for several years now, primarily on the CW shows that compile the Arrowverse which initially saw Melissa Benoist's Supergirl on a separate Earth than the one the rest of the solo superhero shows took place on. However, the events of last year's crossover Crisis on Infinite Earths, merged their universes together so everyone was on one Earth finally. In addition, during that crossover, the TV version of Flash, played by Grant Gustin, actually shared a scene with Miller's big screen iteration to solidify the Multiverse.
With this, anything can now happen and so far has allowed WB to explore different takes on characters which started with last year's Oscar-winning success Joker, which saw Joaquin Phoenix play a separate take on the titular character from the Jared Leto version seen in the film Suicide Squad. Whatever this all means, it also allows Affleck to continue playing the character if he chooses to with rumors flying that if Zack Snyder's Justice League is well-received on HBO Max, the streaming service will want to develop more projects in that continuity, including one for Affleck's Batman. For now, this is all speculation, but speculation is half of what creates anticipation in the multitude of comic book adaptations hitting the small and big screen. You never know what could happen next. Stay tuned!