[Aziraphale tenses instinctively, like he does whenever he feels like he's really put his foot in it.]

It's probably more accurate to say that I was just that oblivious.

[His voice comes out timid and tremulous, and when he finally brings himself to look at Crowley, there are tears in his eyes.]

If I... if I dared to let myself think you wanted me... the thought of being wrong and ruining our friendship...

[He shuts his eyes and sighs.]

I'm sorry. I should have noticed sooner.