Good post, SDG. Being comfortable in being alone is quite different than being "lonely," isn't it?
Even when one is in a healthy, give and take, relationship, it is good to have that alone time.
I recently read this book called
Party of One: The Loners' Manifesto. It's basically a book about people who consider themselves loners, and why. It's a good read for people like myself, and for people that are not loners at all. It gives a lot of insight on things to do on your own, why sometimes its better to do so, and misconceptions/stereotypes of loners.
...and yes, being a loner is definitely not the same as being alone. I choose to be a loner, 'tis my way of life.