I can see why you'd think that, and i don't argue that was the initial attraction, but i disagree. His little smiles make him so happy, and the kiss from nowhere, which it wasn't like, a deep kiss, kisses aren't inherently sexual. and he has a genuine desire to get to know him as a person. I think the idea is that he's led by his wolf instinct first and foremost, and then the intellectual side of him catches up.
Honestly I always thought of that scene of him almost saying "sex" in a sense that, since he was horny at the time, when Natsuo asked him what he wanted, he was going to say what he wanted *at that exact moment*– but then he changed it to what he wanted *long term, for their relationship.* Wanting to have sex with the person you love doesn't mean you love them any less. As soon as Haine acknowledges he likes Natsuo he tries to get physically intimate (the kissing and stuff) but he also tries to get to know him better, as he is genuinely interested in Natsuo as a person. So he's horny, but he's not heartless ╮( ̄▽ ̄)╭
I just think that wolf guy mistook lust for love. Like idk my guy said what he wanted to do w him and that wolfie almost said sex. Like he is making out with my guy to fuck. No affection.