My favourite part of this will always be that they broke up because Aziraphale called their relationship “fraternising”, implying that Crowley wasn’t that important to him. Crowley then decided to Show Him by claiming that he has “lots of other people to fraternise with!” and storming off— clearly assuming that Aziraphale will be lost without him, because Crowley’s so cool and up to date with modern times and he isn’t.
Aziraphale then gets the fuck over this extremely quickly. Next time we hear from Aziraphale he’s cheerfully dancing the gavotte, he’s got an active social life, is learning magic tricks and (according to fanon) probably fucking Oscar Wilde.
When he next sees Crowley, it’s apparently the first time they’ve met since the Incident by the duckpond, and he’s not even slightly overjoyed. If anything he sounds a bit annoyed— “what are you doing here?”
Crowley, on the other hand, apparently got home from the duckpond, realised that he had literally nothing to do now that Aziraphale wasn’t talking to him, and ended up going to bed for nearly a century.
I mean, he’s clearly been around for a bit by the time he shows up at the church , since the the Nazis have already heard of him, but still. He answers Aziraphale with an exasperated “keeping you from getting into trouble!” in a tone that says, very clearly “why else do I do anything?”
That’s not to say that Aziraphale isn’t affected by the argument by the duckpond. It definitely does upset him, but it upsets him because his best friend that demon he likes to fraternise with is clearly planning to kill himseld and wants Aziraphale to help.
(Crowley doesn’t understand this, btw, which I think he reacts the way he does when Aziraphale finally does give him the holy water. Because Crowley assumed it was just about sides, that Aziraphale didn’t want Heaven to find out he was fraternising with a demon, but then he gives him the holy water and he clearly isn’t in trouble about it. He isn’t even worried about getting in trouble, he just wants to make sure that Crowley keeps the lid sealed— it’s the realisation that Heaven was never the problem, and that it was always 100% about keeping him safe.)
But Aziraphale is an introvert. He likes to know that Crowley is out there, and he enjoys the time they spend together, but he doesn’t need it the way Crowley does. He has hobbies, he has a job, he has a willingness to make human friends. He loves Crowley, would save the world for Crowley, would quite literally walk into Hell dor Crowley, but nearly a century isn’t that long for somebody who’s (almost) 6 millennia old and he can cope without Crowley.
Crowley, by this point, is very dependent on his relationship with Aziraphale. He likes to think he’s involved in current events— he listens to popular music, wears modern clothes— but his flat is barely lived in and he doesn’t seem to have many hobbies outside of gardening (and that’s more of a coping mechanism).
And this is why Aziraphale knows that “do something or I’ll never speak to you again!” is the nuclear option, because while both of them will quite happily die for the other, only one of them can’t live without the other and that’s not Aziraphale.
