A couple of episodes ago, K put on a display of lust over the memory of how R looked 15 years ago when trained professionals applied makeup to her face. But compare that to his in the moment response to seeing Janelle in a tight t-shirt. The difference just shows that he was putting on a performance for the cameras with his supposed response to R from 15 years ago, probably to stick it to the women who dumped him. There was no faking the open mouthed lust he had while staring at Janelle directly in front of him.