Good songs about missing someone?

My boyfriend is spending three months on Austria for some singing
competition and i miss him terribly. i was thinking itd be a cute idea
of sending him a song everyday to tell him that i miss him but after
five songs im stuck hahaha.

so i was wondering if you guys knew some good songs about missing
someone or being far away from the person you love.

all songs are appreciated and
thanks in advance :)