I'm an introvert, I spend the vast majority of my time with my wife. I rarely talk to others at work, and I almost never comment or interact with anyone on social media. Talking to people in any medium is exhausting.
My guess would be that the exhaustion the commenter describes comes from the (perceived, and probably accurately so) need to follow certain social norms when in certain social situations. Such social norms wouldn't exist while spending time with one's wife.
On further reflection I think the biggest problem may just be complete incompatibility of interest. Most people I know want to talk about things like tv shows, sports, hunting, taxes, the latest animal video they saw, getting drunk, etc. I try to change the subject to space exploration or information theory but nobody is interested. I have to be constantly careful not to come off as nerdy or patronizing. I'm about to move from a small town in New Mexico to a postdoc at NASA JPL so I suspect I may find myself less of an introvert there :-)
If so, maybe you should try just being yourself around other people too.