I worried about touring alone, but as it turned out in my case, needlessly. There were some real advantages:
1) not having to consult another person, so no comromises on the trip
2) no frustration with another person's lesser/greater riding ability or enthusiasm
3) this is the main one for me- when you're alone you either enjoy moments for their own sake or else you're wasting your time or being dishonest with yourself. For example: you might visit a museum of some sort. Alone, you will stay there EXACTLY the amount of time that you wish, looking at what you want to look at, and the significant social distraction of discussion with a friend is missing. This basically forces you to appreciate what you are experiencing for its own sake; you pay more attention to the museum say, rather than focusing on it more as a shared experience.

Like buzzman said, you'll know yourself a lot better when you get back. I never got lonely either, met lots of people along the way.