I tend to tell mine if he does something that's helpful. I've told him that something he said to me was difficult, but also exactly what I needed to hear. Earlier in the pandemic, I told him that his demonstrating more empathy (saying things like "I know this is really difficult for you" or "I feel for you") was helpful to me and what I needed at the time (and still is).

Like Scarlet said, I also try to be specific about what I need, particularly if I'm sending an email. I might say something like, "I'm just looking for a few words of support" or "I just want to make sure everything is OK between us" (if we've had a conflict or I've shared something that I'm uncomfortable about). This came about because he often seemed to miss what I wanted from emails and would, say, give me practical advice when I wanted support/empathy. He's said he appreciates my being clear in what I'm looking for, as it makes them much easier to answer.

I do tell him when things he says or does bothers me as well, though I've been doing that all along.