LI is pretty manipulative in common ways, reframing abuse to make it seem like the MC wanted it. While It's seemingly intended to be written as the MC not really knowing what he wants/needing to be pushed into wanting it, it is written in a way where we consistently see the MC being uncomfortable, doubting if the LI loves him, etc.
Last ~15 chapters get dubious (LI does stuff while MC is on phone, making communicating consent an issue etc.) to rape (LI’s rut).
During the rut scene,
the MC is crying, begging for it to stop, saying no, etc. and indicating that he is in pain repeatedly. The LI also knots him while he is screaming in pain and begs him to stop, and is depicted as fainting during sex multiple times.
LI acts like he isn’t in control during his rut, but after his rut demonstrates that he was in control of his thoughts and actions (which is unusual for portrayals of a rut in BL). When the MC asks if he really meant the degradation talk that upset the MC, he says he only meant some of it, then admitted that he meant all of it. When asked, he also says that he intended to knot MC and didn't regret it. The fact that he was aware of what he was saying and doing implies that he would have been well aware that the MC was begging him to stop and in pain.
Additionally, the LI gives him a really meaningful gift immediately following them discussing the rut and the things the LI did to the MC. While definitely unintentional, it is reminiscent of the stages of the cycle of abuse, where after the abuser does something horrible they will lovebomb to try to make it up to their partner.
Additionally, in the side stories at the end (sides 7-9), there is bad BDSM etiquette: Punishment play where the MC is not comfortable with what he is being 'punished' for. There is a safe word, but the LI picks it, (which is already bad etiquette), and it's a word that MC does not feel comfortable saying, meaning they effectively do not have a safe word. He is being "punished" for hiding a secret from the LI,
that he wants to propose,
and the LI says that if he does not tell him the secret, he will continue the scene. It's already bad etiquette to intentionally push a sub into a scenario where they might feel forced to safe word, but considering the MC does not feel comfortable using the safe word, it's extra bad.