Sounds like you are on the worst roller coaster ride of your life, and I am so sorry for that. I've been on my own rides, only wishing I could get off, but you seem to be very strong and I applaud you for how you are doing, and the fact your taking the high road.
I have been watching your stitch, and finally wanted to make some observations. Do you think perhaps she is someone who really doesn't NOT know what she wants, with a severe lack of self esteem. Seems she jumps to whomever is fighting for her the most.
W was saying that it's "probably for the best" not to have it if we're not going to be together and that the child would be "sad all the time" without both of its parents.
She said that^^^^^^^^^ That is something she's saying it sounds like to me to KEEP you. OR, to put the blame on someone else other then herself.
I'd also agree with saffie that I really don't think she has any plans on terminating. One doesn't buy clothes for a child they either have no interest in, or are thinking of terminating. ( hate that word ) I think shes trying to find a way to be with the OM and the child, and if that doesn't work- that's why she keeps you on the hook.
However, IF you do think she is capable of that. You could go see a lawyer to prevent her from doing so. You do have rights.
I think your right, shes is unstable, and something went wrong. Do what your heart tells you and stay strong. Good luck, I hope it goes well in the end for you. No matter what you decide or end up with.