"And the Plot Moistens": why didn't Alan dump Kandi for the teacher?
In that episode, Charlie expresses disappointment that Alan isn't sleeping with the teacher at the same time he's sleeping with Kandi, to which Alan says that he doesn't need to when he's got Kandi and that his relationship with the teacher is based on all the things that they have in common in terms of interests and hobbies.
So why didn't it occur to either Charlie or Alan that he should dump Kandi so he can screw the teacher?