I've got to say, I understand a lot of the things you are thinking!
It's a bit of a conundrum... I kind of enjoy being single, but at the same time, I really would like to not be alone. So where does that leave me? Early on in my official singlehood, I was in a bit of a hurry to date. I think my confidence had been torn down to the point that I didn't think it would happen. But it did, and now I'm in much less of a hurry. I've gotten really picky when I look through Match, and almost never contact anyone. I'm not sure what that means, either, but it's how I feel now, so I am really trying not to question it too much.
The kid issue is something I don't have to deal with, so it's hard to say a lot there. I will say that I could see being willing to consider starting again with more kids, in the right situation. Though I'd have to start with some plumbing repair. But the real point is, that I don't think that ship has left port yet, though clearly, it's building steam. You could drive yourself crazy questioning yourself about that, but I don't think it will help!
You know, there's always a chance that either we, or out new partner (or more realistically both or us), will screw up our next relationship. But that doesn't mean we should hide in our den and never come out.
Yet again, it's fear, isn't it? That seems to be the common denominator in so many situations. It keeps us stuck. I know it did (ok, still does, at times) me. I've gotten better at thinking, "What's the worst thing that can happen?" It's usually not so bad! Then I can jump off the cliff!
Oh, the number one thing, before any of this really makes any difference at all... be happy with yourself!