i agree with it being about a husband and wife but i don't think they are literally dying. i think it's just the relationship dying. it even implies he may be leaving by stating taking the pictures and run down the park. by put up your head i think hes implying she wouldn't be affected at all by him leaving and he wants to see some spark of emotion from her because he even said "and what do you care" previously. when he says "it feels like i'm going to lose my mind" it's because he feels like he's trying so hard to keep her from putting up a wall between the two of them but he can't break it down. aka borderline.
i agree with it being about a husband and wife but i don't think they are literally dying. i think it's just the relationship dying. it even implies he may be leaving by stating taking the pictures and run down the park. by put up your head i think hes implying she wouldn't be affected at all by him leaving and he wants to see some spark of emotion from her because he even said "and what do you care" previously. when he says "it feels like i'm going to lose my mind" it's because he feels like he's trying so hard to keep her from putting up a wall between the two of them but he can't break it down. aka borderline.