We talk A LOT about emotions (DD is 2 also) and even when she was really little she had one of those cloth activity books (you know the kind with the buttons, zippers etc) and in it there were faces with different emotions. We'd pick up each face at a time, make the face, make the sign for the face and discuss the emotion.
I don't know if you do TV but DD loves Kai Lan. In it they talk a lot about emotions, discuss out to identify when someone is angry/sad/nervous etc and gives examples of ways to deal with that. DD begs to watch it non-stop and will retail the stories and how the characters solve them. Many times if we have an issue come up we'll discuss on of their episodes and it helps her work through the problem.
Beyond that as a family we're pretty upfront about everything. If we're upset we say it (both between DH and I or between us and DD) and say why we're upset and figure out ways to deal with it. One suggestion too is if he says he's sad talk to him about how you get sad sometimes too (maybe give a few simple examples) and then discuss things that help you feel better.
