I thought it was a form of birth control... so they aren't stuck with a bastard child.
When I go to a movie and decided it was too fucked up and not worth my time, I would walk out and walk away.
When fucking and decided the fucking not good and no meaning, what for to continue the humping and humping, I too will walk away without a look back.
Not waste time and can have a better fuck elsewhere.
That cunt will have to make do with her own fingers and a dildo.