Via Capitol Records, Calum’s label, he described the writing process and meaning behind this song

‘You Are The Reason’ started out as a song about something completely different than what it is now. It was originally written from a fragile place of anxiety and not knowing the cause of it, so the song started to become ‘Without A Reason’. But as we carried on writing, we realised how every relationship has difficult times but you stick with it because the love you fundamentally feel for the other person overrides everything else […] I wrote this song to say thank you to those special people who make our lives better, simply because they’re in it.

“You Are the Reason” is about being in a difficult relationship while in love. Calum described the meaning more in depth through his label Capital Records

“You Are the Reason” started out as a song about something completely different than what it is now. It was originally written from a fragile place of anxiety and not knowing the cause of it, so the song started to become “Without A Reason”. But as we carried on writing, we realized how every relationship has difficult times but you stick with it because the love you fundamentally feel for the other person overrides everything else