Separation from other people will do a number on you for sure. Hell, even having people around but people you don't feel like you can talk to will eventually eat away at you. One of the greatest benefits of marriage is being able to let all of your shit out with someone who doesn't have a stake in it and will pretty much accept whatever you say while you're griping. I know my wife is mostly ignoring me when I bitch about work or something, but it's still cathartic. And then, I don't go griping to anyone else.
Same thing with her. She gripes at me, I kind of half listen and support whatever she says, and then she can go back to work without exploding like a crazy woman.