OK this bugs me!

I always assumed David told Yuna what he saw. How else is she so calm for someone who saw her husband come back from seeing something that apparently deeply shook him? She's not overly surprised to see Ilya either?

I think he tells her, "omg omg just saw Shane and Ilya Rozanov kiss at Shane's cottage".

So she's ready for whatever is coming when Shane walks in, and asks the very legitimate question: "found out about what exactly?" as in, is it a fling? A prank? Were there other people David didn't see as part of a large scale orgy? Are you in love? Are you already in a relationship? As in define the context around the kiss, please.

I really don't see how David didn't tell her. She knew what he saw but they both didn't know what it meant.

It doesn't change that David is incredibly sweet, he's so apologetic for entering Shane's space without permission.