"The thought of him or seeing him stops me in my tracks and makes me shake to my core, yet I can still have the feelings here of.. where did it all go wrong. Could I have done something different (I know I couldn’t have), it just makes no sense to me. 10 months of me and mine thriving, no contact, nothing and I feel this weird feeling. Will I always be like this."
I know it's trite, but time is your friend here. What your brain is doing is processing the abuse: looking at the past, reframing it in the light of what you know now, reviewing what and why you felt at the time of the abuse.
All of this processing means that you are literally rewiring your neural networks. This is a physical process that takes energy and time.
It also means that during the processing period, you run down familiar neural networks occasionally, which link to certain emotions. So you get flares of memories and loss, and it leads to you missing the abuser while your brain is telling you, "Stop It! He was horribly abusive!".
I read somewhere that for every year of abuse, you need a year of recovery time before you are fully freed of it. That kind of tracks with my own experiences. However, you can probably speed that up with therapy.
So what you're going through is normal imo. Be proud of yourself that you got out, that you were strong, that you saved your child and yourself. Give yourself time and above all compassion.