Q and Eve Monneypenny in the Sky Fall fic, so you were never a saint. Eve constantly fusses over his appearance and frequently crashes to his house to cook or watch TV with him. In the MI6 HQ, they are either bickering or ranting about their work to each other, to Bond's amusement. At one point, they even consider getting married to each other if they're still single in their middle ages. Despite everything, they are not in a relationship.
Escape From The Hokage's Hat: While out on Not a Date, Naruto goes on rant to Hinata about how the ramen stand they passed was substandard and not worth their time. Hinata gives him a smile, lightly pats his hand and tells him he is very knowledgeable. Naruto pouts at being humored.
Son of the Sannin: Jiraiya and Tsunade have to live under the same roof while they raise Naruto together, so they end up as this for the first couple of years. Of course, it doesn't take long for them to become an actualmarried couple.
Advice and Trust: In chapter 5 Shinji and Asuka stage a fight during lunch break so that nobody suspects they are together. However they are not very good actors and rather a fight between two friends that do not get along well it seems an argument between two persons have been married for years. When Touji says so, they blush profusely and shout in unison "It's not like that!" Of course, their synchronized reply only reinforces the effect.
Touji: Oi, oi, what's this? A quarrel between husband and wife?
The Child of Love: According Touji, Shinji and Asuka not even are married and already behave like a married couple:
Asuka: Shinji! Listen to me, dummkopf! Shinji:[surprised] What is it, Asuka? Asuka: Hikari told me about AXL's Game Center! It sounds fun! I want you to take me there, okay? Shinji: I don't know if... Asuka: Stop being so hesitant! You're getting on my nerves! Toji:[to Shinji] Not yet married, and she's already henpecking you...
Evangelion 303: As soon as they met, Shinji and Asuka bickered. They were attracted to each other, argued constantly, opened up each other and talked about personal issues... and as soon as Shinji moved in the base Asuka started to spend her whole free time in his home, sleeping in his bed, using his shower... and Shinji cooked for her. When he left for a week Asuka stayed the whole time in his home... and that was BEFORE they got together and long before they got engaged.
HERZ: Asuka and Shinji already argued like an old married couple before becoming one. In chapter 12 their bickering is hilarious.
In Neon Genesis Evangelion: Genocide: After they work out their differences and become the Official Couple, Shinji and Asuka's arguments are less violent and hurtful. Asuka starts sounding like a wife nagging her husband, and Shinji like a husband pretending to listen to her.
Inverted in The Second Try. After being told the secret, Misato mutters Shinji and Asuka used to bicker Like an Old Married Couple before, but now that they ARE one, they act like new-found lovebirds. Shinji and Asuka explain that is -partially- because they are hormone-driven teenagers again... without Belligerent Sexual Tension separating them.
The "Hey, look, the newlyweds are fighting!" line from Toji is revisited, and Shinji and Asuka both try hard to act like they did the first time, except Toji notices that the two of them are having a hard time containing their laughter.
Shinji: You know, if you flashed the class, I bet you could kill half the male population. Asuka: Toji's an idiot and Rei's a liar. Shinji: Toji's been hospitalized and you never denied that quote from Rei. Asuka: Alright, shes a horrible exaggerator! Happy now? Shinji: No! This shirt was brand new. Asuka: Gah! Why must you take her side? Shinji: I'm not. I just enjoy winding you up, or have you not figured that out by now?
In Prison Island Break, Sonic the Hedgehog and Shadow are cellies. At first they hate each other but their relationship evolves to this, especially since they have to spend every night in the same room together.
In X-Men: The Early Years, Scott Summers and Jean Grey argue, bicker and fight like an old married couple long before becoming a married couple.
In The Darwin Chronicles, Scott and Logan's endless bickering and ongoing insult war has led to amusing misunderstandings among people who don't know better.
Logan: Yeah, you're nodding, Blue, you know what I'm saying and we start getting into it and I'm winning, of course and this guy, this older guy comes up with this other guy and their dog, and he he says Scott: (smirking) He tells us he and his partner used to argue all the time when they first got their dog. And I learned that Logan's healing factor can help him recover from an aneurysm pretty fast.