I don't think that you were in the wrong for cutting ties with your friend. That is something you needed to do, to bring yourself closure with your ex-hub. Some things about your friend may have annoyed you, like her slowness. But I don't think that was a big deciding factor in your decision.

I do think that your last comment to your friend were painful to write, and very painful to read! I suspect that is where your sense of guilt is stemming from. To alleviate the guilt that your feeling inside you can apologize to her for your last words. Tell her that you still feel hurt by your ex-hub, and that is something you need to work on. Just say that you really didn't mean to hurt her feelings. Can she forgive you please? That will help you feel a lot better.