You may think that the song tells about two people who are going to kill themselves together...
But I personally do believe that the song tells about two very best friends. The other one has difficult time in her/his life and her/his friend tries to help by saying that she/he would always be there, even if life will be really "dark".
I think the song cannot tell about two lovers because of the line "Cuz you're not the only one". That is something you say only to a friend... IMO
You may think that the song tells about two people who are going to kill themselves together... But I personally do believe that the song tells about two very best friends. The other one has difficult time in her/his life and her/his friend tries to help by saying that she/he would always be there, even if life will be really "dark". I think the song cannot tell about two lovers because of the line "Cuz you're not the only one". That is something you say only to a friend... IMO