I can understand how that would arise.
I came to poly via cheating-so lying, even for "little things" is a big no-no in my world.
I would have been honest and told him "I know you want to make me feel better and I appreciate the thought-but the truth is that what makes me feel best is when you support me as I work through the emotions I'm having. It just upsets me and confuses me when you try to make me laugh-becuase then I am not being authentic about my emotions; which means I'm lying to myself and you."
Sometimes; we don't even realize that what we are doing is creating a dynamic where lying is "natural". But if we start consciously paying attention, we can stop it. The more authentic and true we are to whatever it is we are really experiencing, the more we can learn and grow from it (as can the people around us).
"Love As Thou Wilt"