To explain a little here - ahem! The Duke is dissociative due to the trauma of his parents' deaths. That's why he has an anxiety attack when he loses the pendant and also why he's dazed all the time. He's not just 'soft', he's emotionally detached. Like when he's pushed down by a stranger on the street, he just lies there and focuses on the moon. He literally cannot react any other way. The Spinel, on the other hand, is in a state of mental exhaustion. He's desperate. Like tackling someone on the street and taking the pendant. He, himself, while in the cell, was thinking 'oh, I just did that, what?'. He's desperate to the point that his thoughts are messed up. He bet on the Duke buying him so he could eventually gain any kind of leverage to escape and rescue his mom and sister. That's why he offers to be the Duke's bed partner. It's not about liking the Duke or because the Duke is pretty at this point. He's trying to trade s** for anything he can get, anything, because he thinks that's what the Pels want from Spinels. And then, when he thinks that the Duke has a lover, and that lover is the Prince of the country, that plan doesn't seem like it'll work out. He can't trade anything, he's worthless. He retaliates, tries to get some kind of control, by forcing himself on the Duke. "I can do it better than him" should not be treated as 'like me more' but rather as "I'm valuable!". This is, indeed, ra**. It's supposed to be ra**. Dev himself admits to that and understands it. That's why he's saying 'I'm insane'. Because he understands that at that moment, he really is 'insane', and he's not a good person. But he's desperate to live, to find any means of living, so he can save his mom and sister, so he doesn't really care if he's 'good' or 'bad'. This doesn't mean he wants to hurt people and he's not a sexual predator. This is actually a pretty good depiction of these respective psychological mechanisms, given each characters situation.