Remember, his goal is to get Karen to reach her limits and jump him. Part of that is making her not only affectionate for him, and horny for him, but also frustrated and desperate. This is all part of the plan.
And who's jealous now huh? should have gone for him when he was trying so hard now just watch and suffer u karen! (Obviously I'm still waiting for development between them and the "comedy" from Haru's side).