Being a shepherd means that you depend on your sheep and you have to protect them; you have to, even at great risk to yourself. A shepherd might very well have to lay down his own life to protect the sheep.
In the same way, caring about another, a parent, a friend, a romantic interest, a spouse, a child, a grandchild, exposes you to risk, certainly emotional risk, but often physical risk as well. To love another is to make yourself vulnerable. It goes with the territory. The bonds of love make us vulnerable, we depend on each other, and so we can be hurt. And in families, those hurts happen, but laying down our lives for each other, as the good shepherd lays down his life for the sheep, is part of what makes us human.