It's 'lonely at the top'. [=powerful and successful people often have few friends]
He was/felt 'lonely' without his wife and children.
the 'lonely hearts' section of the newspaper
(..) You may keep your sanctity, Scarlett. It'll work no hardship on me. Do you mean to say you don't care? The world is full of many things and many people, and I shan't be lonely. I'll find comfort elsewhere. Well, that's fine. But I warn you. Just in case you change your mind, (..)1939 Gone with the Wind