At first, I thought the song was written about his mother.

But, like Hozier's use of the pronoun "she" in "Take Me To Church", he could be talking about god. He could have taken a path in life that (in his mind) god wouldn't want for him.

He could have easily said to God, "that's the last you'll see of me", referring to the church's disapproval of his sexuality - so he walked away.

What if "home" was his faith. As a gay man growing up in the church was difficult. So it would be surprising to himself that he had a longing to be back home - a place where he could be himself and practice his faith.

I don't believe that any one particular interpretation is more correct than another. This is just another way to look at it. Songwriters often paint themselves into a corner with pronouns. If we as the listener stop being so literal, we may get more out of lyrics than we expect. We tend to want everything spelled out for us. "What does this song mean?" as if the songwriters meaning when he wrote it must be literal and specific. Art doesn't work that way.