Just to play devils advocate and speaking from personal experience, I think you may find that she has very low self esteem. She probably sees that you have a great kid and feels the need to point out any minor faults because it makes her feel better as a parent. I'll bet she may be struggling with parenthood and won't admit this even to herself for quite some time. Hang in there (maybe at a distance) she probably needs you more than you need her.
kelle, she sounds like a pretty difficult friend to be around.
Sometimes, we hang on to friendships just because we've been friends for a very long time. I think you should begin to distance yourself from her, and develop your other friendships.
Also she is affectionate and loving...when she wants to be. I'm always loving to her son. Know don't get me wrong. I'm not saying you should just put my son on a pedestal. I'm not saying that whatsoever. I don't get how you can sometimes be loving, other times not and feel you have authority over me as a mother
I do have to add. She always seen herself as the teacher and me the learner, even before kids. Also I would say 70-75% she is grouchy in general.
You've got kind of a weird dynamic going on here, I think. It seems to me in your friendship, your friend perceives herself as the "teacher" and you're the "learner". It would be one thing if she were sort of snappish with him, and grouchy - that would mean he was just irritating to her. But she's not. She is affectionate and loving.
So. In general, in your relationship, has she been the one who is on track, doing things very responsibly, and she's been there to help you out of a lot of sticky situations and has never needed - or asked for - your help in her life?
Some women gravitate to that kind of relationship. They're the giver, and they prefer friends who are in need of help. Makes them feel needed and a little superior.