A Lot of Water Under the Bridge
Some event or incident has occurred and cannot be changed.
There is no point in worrying about it anymore.
You can get on with life as it is today and forget yesterday.
Time has elapsed, and memories are cherished,
but we cannot dwell on them as though the circumstances still exist.
The world is constantly evolving and never stays still. Nor can we!
From Casablanca, the romantic drama, staring Humphery Bogart and Ingred Bergman,1942
Sam, played by Dooley Wilson, had the iconic line, and there was a lot of water under the bridge.