kinda a personal take on the this, but when zira fidgets with his hands, I can see two things from that, crow either: one, saw the pinky ring and absence of wedding ring and that's why he said boyfriend instead of husband or two, he saw him fidget and since we can see az doing the same when nervous even if his face doesn't show it, he just kinda realized what was happening and tried to change the topic to calm the bby down and honestly I'm hoping it's both
lots of you were mentioning this, so i’ll explain a little :)
Crow and Zira are the most outwardly anxious out of the 4 of them. Crow isn’t used to an Aziraphale that’s so blatantly nervous; Az does have worries but the way he expresses them are more subtle. so Crow is thrown off because he’s not used to this and Zira’s anxiety is triggering his OWN anxiety. he’s like, quick! time for a distraction! it’s for the both of them XD
the fidgeting that Az does in the first part isn’t suppose to be purely from nerves. when he learns that AJ is also a Crowley, he immediately reaches for his ring because his subconscious is sending warnings to him. but he brushes it off by telling himself he’s over reacting.