Introverts deal with things internally, Extroverts deal with their shit externally through other people.

Talking about things is how an extrovert works through their problems and they think everyone else is the same, they think introverts "bottle things up" and need to "get everything out into the open". The introvert resolves their emotional problems in their head, they just need some time and space to think things through. Discussing doesn't do much for an introvert, the only reason they would want to talk about a problem is if it actually solves the problem.

If your partner is someone who will listen and change their actions, then there is a reason to talk about problems in the relationship because talking might resolve them. If you are upset about the death of a friend, stressed at work, angry with yourself about a stupid mistake, or if your partner is someone who will just get defensive and talk over you.. then there is no point discussing these things.

LPT for the introverts is to practice stating your emotional problems in a relationship, you don't have to discuss them but just a short "FYI I might seem moody today, I am thinking about the death of my friend" "No, I don't need to discuss it but thank you" "No really, I don't need to, I was just letting you know so you..." "It's not about you, please dont talk over me I wa..." "but you just did talk ov.." "WTF do you mean that the death of MY friend affects you mor.." "uh huh" "ok" [grunt a few more times until they stop talking and walk away].

10mins later the extrovert says "Sorry, I didn't mean those things I said but I'm glad we got all that out into the open, I feel much better now, what should we do for dinner?" and the introvert has just made a permanent mental note that you are insane and never to mention their emotional problems with anyone again.