The moment that Caleb mentions donut, Essek knows exactly what he is doing. It is a gift for Jester, a wonderful gift that will no doubt make the tiefling happy-- he wishes he could reveal himself to however at this particular moment, he is not sure of the wisdom of it.

He does intend to tell Caleb, but there is a bit of baggage there because he finds that his choice had been rooted in selfishness, he had wanted to find some way where he could see Caleb a bit more regularly-- he'd not said anything of his affections because well, Caleb deserved someone who could ah~ share time and proximity with him.

And as Essek was it was impossible. But perhaps underneath the guise of Seth?

"This friend sounds very fascinating, especially if you are magicing 'baked goods' for her."