I've known people who are happy and fulfilled living alone, but it's hard for me to picture myself in their shoes.
My wife and I have an awesome relationship. I would be okay-ish, but it couldn't hold a candle to what I have now.
The big bright spots in my life are my work, my relationship with my wife, and my kids. I would have more time to play video games and consume media, and I'm sure I'd have some more friends and hobbies... But it's hard for me to picture papering over her absence with friendships and hobbies.
I understand not being as happy or fulfilled without a partner, but _miserable_?