Here are three observed differences between a newlywed and a crusty old married:
When the newlywed doesn't want to see a movie that her husband suggests, she murmurs gently: "I don't think I want to watch this show."
When the crusty old married doesn't want to see a movie that her husband suggests, they have the following conversation:
Husband: I want to see James Bond.
Crusty old married: Not free not free not free!
Husband: Busy doing what?
Crusty old married: Just not free. Don't ask so many questions.
When the newlywed's husband is too tired to go on daytrips with her, she lets him rest at home.
When the crusty old married's husband is too tired to go on daytrips with her, she says: "I don't care. I need a tripod carrier."
When the newlywed asks her husband whether she's nice to him, he says: "Mostly."
If the crusty old married were to ask her husband whether she's nice to him, she is sure his answer will be "you should stop using me for kickboxing practice".