I've seen and heard this from other parents, but not my own. It's just a question I've had for a long time. There truly must be more people (un)fortunate enough never to have witnessed this from their parents either.
Where do you learn to love, if not from them? Television? Books? Then again, any remote physical displays of affection by them seems so fake, knowing that their true feelings towards one another is nothing but an irreparable scar.