To me, it sounds like you're actively seeking relationships just because you can't be alone. Maybe you should take the time out and learn to be happy in your own company first. That way, you will be more likely to choose someone who's good for you and who you want to be with, as opposed to someone who's just there.
I can tell you (and I'm going to assume a lot of guys think like this too) that when I start going out with someone who doesn't seem to like their own company and always wants me around, it irritates me. That's just too clingy and annoying and claustrophobia-inducing.
Fear of being alone is not a good enough reason to be in a relationship.
Don't be too hard on Kitten, she may not be to blame as much as she thinks...
One benefit of being alone is that I get to do a great deal of random pondering and I've thought about this same topic:
When you are alone, you get used to your own company, your own way of doing things, your own way of dealing with friends, family and strangers, your own way of presenting yourself, your own way of dealing with enjoyment and misery...
Now you find love and all of a sardine your singularity gets shattered. You have to re-acquaint yourself with you as a partner, no longer a rogue entity. For obvious reasons you can no longer conduct yourself and all above-mentioned topics in exactly the same fashion as you used to.
This is where problems arise and people say "you've changed, you were so much cooler when we met" - yes, because you met as singularities. Not as partners...
-flip side of the coin-
If you've constantly had boyfriends/girlfriends since early school days and you jumped from one relationship to the next without a real moment of personal growth in between, then it would make logical sense that you have acquired the skill/feel for co-existence. Ergo, when you are single - you feel out of place. Your comfort zone is not your own company, but that of others.
Please tell me if I'm completely wrong here, as I'd love input from differing perspectives.