Journey, My H does the diagnostic scan as well. Also, he puts a lot of pressure on me to be chipper when he arrives home. Now, with me being a 7, this is much easier on me that I would think it is for you. Still, somedays it is a struggle to muster up a smile when D3 has stuffed something down the toilet and I have to fish it out with my hands. KWIM! Anyway, I sympathize with you on this front.
What works for me is to keep in touch via email and tell him what's going on..."I'm not in the best of moods, because of ABC. I will try to cheer up before you get home, but if not, don't say I didn't warn ya!"
This heads up helps us both detach from the other...I am flat out saying it has nothing to do with him; he is aware before doing the DS that it has nothing to do with him.
And if it does have something to do with him...well, the DS isn't usually necessary cause I've most likely run my fat yap already and let him know about it. LOL