Hetalia Sad!Headcannon [Used Google Translate]
On August 4th, Sweden got into a war with Russia and sadly lost. Right before he left with Russia he went to Finland saying
"Kommer du alltid vara min fru" and left Finland with tears streaming down his face. Every night since then Finland keeps replaying those words in his head and sleeping in Sweden's old room, never leaving. The rest of the Nordics tried getting him back to normal, but nothing happened so far