Dating/Friends With Introverted Guy

I found a thread here on introverted guys, but it was dated a while ago, so I hope nobody minds I start a new thread.

I have a friend guy who is introverted to whom I like, of course. I am a bit introverted myself, but I want to open up and express my feelings comfortably and try to learn to be an extrovert and all. I was wondering in any kind of relationship with an introverted person, is there a constant need to pick up the "slack" on your end when together? Will the introverted person ever, ever truly and flat out tell a person how much they care and openly feel comfortable with a person they are with? Or are they always going to hide in a corner and not say everything that is on their mind?

In other words, is being with an introverted person(once they are comfortable with you) a lot of work to keep going in a relationship or is it just initially during the start out?