Scar tissue has no feeling.
One protects one's heart. One takes it and encloses it in...marble, see-through marble. It then does its work. It beats, it lives. Maybe it even loves, but when that ends, it does not shrivel up and die, it doesn't break, it doesn't hurt and one doesn't worry about the scar tissue making it ugly.

One hopes that that's the way marble casings work.