Well, it seems to me that "The talk" isn't needed if the SO already knows, but it's almost certain that there will be a lot of "A talk" opportunities afterward.
Now, if the SO is still unaware of something (I'm thinking of transitioning, I want to go on hormones, I have a secret life you don't know about, etc.) -
then there can certainly be another "the talk", about that subject.
I guess the difference between "a talk" and "the talk" is the magnitude of the discussion - and maybe an introduction of something new to the relationship.
