Aziraphale and Crowley have been together as friends since the 4004 BC. Crowley later on grew a crush on Aziraphale, it got more noticeable has the years passed by of their immortal lives.

But, once Crowley found out Aziraphale was leaving earth to go back to hevean to be an Archangel, made his blood boil. Even if Aziraphale told him he could join him, he didn't want to.

“You idiot. We could've been us.” Crowley said, holding back tears behind his glasses.