I believe the theory to be true because it makes so much sense
The song really is about two people in a relationship who can't go public with it and in a recent concert "The Temper Trap" (the band who sings it) dedicated it to two very close friends that had recently come out of the closet... I think it's such a coincidence that Harry would get some lyrics like that tattoed when they'll stay forever with him.
I JUST LOVE THEM SO MUCH!
Also, I'm not one to mention normally this but I find weird that after the tattoo thing apparently
she is going back with the boys to America
