It is obvious to us since we are playing a NTR game but you have to understand Kirito has no reason to distrust Asuna. He thinks Inoda is no threat to him. His sex issues with Asuna he thinks it has been resolved. Asuna has been prioritizing their relationship like he does. She is changing but he has not noticed. So really Kirito has no reason to think Asuna is cheating.
It would seem that everything is correct, but with one exception. A girl who values her existing relationship, but at the same time seeks "variety/pleasure" on the side, will never do as Asuna does. For the credibility of this story, half of the existing scenes need to be boldly cut. For example, remember the scene when during a chat, Kirito went to get a package, and Asuna rushed to Inoda's penis. And then she, with her bra half-lowered and her chest/face in sperm, stupidly turned away from the monitor - like her back was tired. This scene is extremely stupid. Any man would have sent her after that. It just needed to be played out differently, if you really wanted to show Asuna after sex.
Kirito returns - hears some fuss, but there is no image (Asuna is trying to tidy herself up and wipe off the sperm). He calls Asuna. After 10-20 seconds, the monitor turns on. Kirito sees that Asuna is a little disheveled, and one nipple is sticking out of her bra.
K - Asuna, what happened? Why did the image disappear and what's wrong with your appearance?
A - I accidentally touched the cable with my foot and the connection was broken. I had to crawl under the table. There. I'm a little disheveled.
Asuna notices that her breasts are sticking out.
A - Oh, and my clothes slipped down a little. Sorry, sorry. I was in a hurry and it was so awkward...
Do you want more dirty talk? Then we can make it so that Asuna didn't have time to wipe off a couple of drops of sperm.
K - Asuna, what's that stain on your chest?
A - Oh... that's... You were just gone for so long... And I missed lunch today because of work. So I decided to eat a hot dog. And I splashed myself with sauce. Because of this, I jerked in surprise and touched the cable with her foot...
If Asuna "still loves Kirito" at the same time, then to the question about the taste of the hot dog she can answer - well, a hot dog is a hot dog - nothing special.
If she is already dissolute enough and wants to "make fun" of Kirito, then you can start a dialogue about how awesome the hot dog was. So big and juicy. I've never tried anything like that before. And the sauce is great - thick and with a rich taste!
K - Oh, I would like that too! Next time, let's eat together!
A - Cough... cough... (choked). Well, I don't know... We can try...
Asuna can simply wipe off this "stain", or she can collect it with her finger and, closing her eyes, lick it off - Oooh, this wonderful taste! I would gladly eat more!
Well, and so on, the scene can be developed. And there is an explanation for everything and Kirito has no reason to suspect Asuna.
And then he came back, and she turned away from him and was like - that's it, you've had enough. I'm tired, get lost!
And it's not that Kirito thinks Inoda is somewhere else. In theory, Asuna could cheat on him, for example, with an employee who delivers food to hotel guests.
Can a girl behave the way Asuna behaves in the game? Of course she can! Only this girl doesn't give a damn about her current relationship. And if a guy catches her, she will calmly tell him - and get lost. I haven't given a damn about you for a long time.
But the author here is trying to make Asuna who values her relationship and there is a wild inconsistency in her behavior.
Somehow that's how I see it all
oh, and also
Yes, the main part of the game could be said that Kirito does not believe in Asuna's cheating, since he himself is extremely honest in this regard.
But excuse me! For 2-3 updates now he allows himself to get blowjobs from girlfriends or have sex (since I'm currently skimming the game, I can't say for sure, but it seems like he wasn't drugged during the last massage with Liz? But even if he was, then, especially in the last update, he had one situation after another). And Kirito is like, holding his dick in Sinon's mouth - What, Asuna is cheating? Come on, that can't be!
Lord, what a stupid and inconsistent plot! (((