This is a massive relief to me: not only am I introverted, I'm also a little socially anxious. How much quiet time do they need before they're up and ready to talk to people again?
It's now recognized that a few moments of silence and listening to your own body every day have health and psychological benefits, and that peaceful isolation is part of a strong relationship.
My dude knows everybody, and can talk to them at great length wherever he is: on the street, at the supermarket, hanging upside down.
It's now accepted that if I've used up my social energy for the day, I'll drift off from these conversations and look at something else, or just quietly listen from the sidelines.
This can be one of the trickier things to negotiate in an introvert relationship: their quiet time is deeply necessary for their internal social batteries, but it doesn't have to mean they're isolated. So don't deliberately leave your partner at home while you go to parties or gatherings because you think they won't enjoy them, or be surprised when they want to host a party; introverts get lonely too!
You can bond just as well, and feel just as connected, by being quiet in the same room — or, indeed, letting them be quiet and read in the next chair while you chat on Skype. And even extroverts can have their quiet moments; it's very rare to be entirely one category or the other.