I don't know since when this saying became popular on the Internet.
Twelve strokes for family, twelve strokes for friends, twelve strokes for lovers, and the note I gave you is eleven.
Friends are almost friends, lovers are almost family.
People who are in secret love will have such a feeling, worried about gains and losses, extremely hypocritical, full of grievances but nowhere to cry, after all, I am not even qualified to like you.