“to draw the final stroke”
In German the term “Schlussstrich” (“final stroke”) is now only used in the expression “einen Schlussstrich ziehen” (literally “to draw the final stroke”), which means to really want to put an end to something (mentally). I don’t know how people would do that though. How do you just decide to stop thinking of, say, someone who has left you? So that’s maybe a reason why the intention to put an end to something or to forget something or someone needs an image like the “Schlussstrich”. In the end you have to keep on “deciding” or “stating” that things have ended many many times I suppose.