I once wrote, " I live alone with my wife and family." It was true, I did. They had a bare hint of what had been a who and what I was even then. I wasn't hiding, but I wasn't there. That seems as though it should be sad. Sometimes it was. Christmas was lonely. My birthday was lonely. Other times not so much. Being alone was the way I was raised as a child. Out on the prairies, walking the fields, doing my things, exploring the world. My father told me once after my return from Africa that I had been gone since I learned to walk.
Sometimes you are alone because of betrayal. You are alone because you are unpopular or standing for an unpopular thing. Often, you are alone because you prefer it. Many times, because you are shy, you will be alone. Sometimes you are alone because you are depressed and withdrawn. That's the bad alone. That alone you need to find someone to help you with.
Solitude requires you be alone. You can have solitude if you have cats, even with three cats in your lap you are still alone. You can't be alone if you have a dog. Dogs do not allow solitude.
There is a skill to being alone: