I think maybe you could communicate what you've said here without actually asking 'T, can you please be a bit more emotional?' Not because I think it would be wrong to ask, by it might make it less stressful for you and easier to have the conversation if you don't ask directly. You could say 'I find it hard when we are talking about -- whichever things -- and sometimes I feel as if I'm not allowed to be upset about it. I wish I could be able to show my feelings a bit more. Do you feel upset about it? I think it helps me a bit when I can see how you feel about the things we are talking about.' Or something like that.