I'm kind of annoyed with how the bed-sharing event was presented: touching, blushing, heartbeats, speaking of being a family, focus on bust and hips, sudden movement to take her hand and shoulder, what seems to be the start of a confession of love (or lust), and, in the following chapter, shiny skin in the morning, which is “anime for MC getting laid last night” as Talith said (although it can also come from solo play). Even the title of chapter 18, “The Indecisive Two”, in context looks to imply a romantic decision. Afterwards, there is no hinting or acting different. Although I'd expect some reflection on it from Asuta, Ai Fa could very well be nonchalant about it because of how she is and how her people are (like when Asuta was thrown into the women's bath). Lack of change could also be taken as them already having been that close, just not taking that step. All this is fine for a their-first-night event.
I was still curious though, so I went to read the corresponding light novel chapter (V4C2.6), and they decidedly do not do it. (Also skimmed the web novel chapter (#86), called “House” (家), which seemed to have the same content.) There are some interesting differences to the manga. In the manga, they enter and lie down and talk: Asuta defers the food stall decision to Ai Fa who says that he's looking for excuses not to do it, and then asks him to let her do something for him as a family. Then doki-doki and fade to black.
In the novel version, they enter the room, with him feeling nervous (for romantic/sexual reasons), and he asks her opinion about the food stall: not a problem, it's just money, but they agree that Kamyua Yoshu is mysterious. The responsibility is his (Asuta) and Ai Fa's, she says. But he still hesitates about sharing the load, which hurts her: she feels like he is rejecting her and her house. He assures her that it's just cultural differences, and that they will understand each other better with time. She still fears not having time (death or disappearance), but he comforts her (future is uncertain but time until death or disappearance is theirs), and she seems near crying for a while. Gathered, talk returns to the food stall: he'll try, but now fears troubling the village as an outsider, which irritates Ai Fa who tells him to think of himself as a person of the forest's edge. Having talked, she lies down and calls him to the bedding (he planned on sleeping on a rug). He (kindly) refuses, even explaining that his people only share bed as child and parent or husband and wife, but she again seems to feel rejected and turns away. He gives in, because “Ai Fa had firmly declared that she didn’t want to take me as a husband, so there shouldn’t be any misunderstandings from this”. He lies down next to her, so she turns to him, with a maybe first-ever happy, joyous look (“You should have just listened to what I told you from the start…”). She says that she believes in him (re: food stall) and will regret nothing, and is proud of him and glad to have met him and taken him into her clan. She falls asleep, while he has a sleepless night looking at her adorable face.
Having read that, the manga annoys me a little. There's quite a bit of interaction lost in adaptation, but what's left points so hard to the opposite that it reads like fan fiction, like the manga artist read the novel version and thought “okay, fine, but in my version they'll be doin' it!”.