pine away
To lapse into a period of intense depression or melancholy due to one's longing for or grief over someone or something. I stayed back in Seattle pining away, while she was over in Europe having the time of her life. My grandfather pined away for nearly a year after my grandmother died, until eventually his heart gave out and he passed away as well.
pine away (after someone or something)
to waste away in melancholy and longing for someone or something. A year later, he was still pining away after Claire. Still, he is pining away.
pine away
v. To wither or waste away from longing or grief: After its owner was killed, the old dog pined away and died.