You are at a good stage. The celebrating in a small way and being proud of yourself in a small way is actually a massive massive thing OP. I remember this well.
My experience with this was decades ago but let this wash over you and leave. Like air. It comes and goes.
As I said earlier it will take you many many months before you heal fully from this experience and in fact it will always be with you. I left mine after four and a half years. I lived with him for six months but had to move out as he was too toxic and full on. I stayed though because as a PP said upthread, God knows why but it's like crack. I think it's the deep seated urge to heal that person and get them a better life or something. It's beyond my analysis.
I was driven demented because he was perfect for me in every way apart from his subtle and sometimes not so subtle abuse of me. This made me seem to want to crave his approval or something I dunno.
One day he pushed me just too far and something snapped and I saw him. I saw him and I saw myself. He was just chuntering on in his normal way but suddenly it was like the earth shifted beneath my feet and I grew ten feet tall. I knew then that my lesson was learned and I was leaving again and I would actually stay away this time.
I didn't say anything as I had to be careful. He had been violent on one occasion and accidently on purpose physical on others. I knew he would lose the plot if he realised but there was such a fundamental change that he knew straightaway. Even my voice went a bit deeper! It was like a light came on inside me.
I pretended I had a headache and went to bed. I knew he would then start to do something noisy but on this one occasion he didn't. I lay with a blanket over my face and I was so so calm. I could see my future without him plainly in my minds eye and whereas before, a life without him felt unbearable (I had left many times) this time it felt completely normal to be planning my escape and staying away and how to do it.
The following day I continued the 'headache trick' and he went to work. As soon as I heard him drive away I was up and like a dervish getting my stuff together and throwing it in the car. I was terrified he would come back as he would have killed me without a doubt.
After I left he wrote me letters. Lots of them. I was in a lot of emotional pain. He was intelligent and funny and just extremely interesting as a person. I loved the essence of him but the dark bit of his personality was too much for me and it made me ill for the whole time we were together. I wasn't me around him. I was fighting fires the whole time. The brilliant times were just so brilliant that it's almost the memory of them that kept me hooked in when he was being abusive.
A PP said it was like having a limb chopped off and it was. I was in absolute mental agony. I didn't start to not care for two years. All of this was in the 90's and I have been married to a wonderful bloke now for 18 years but even now there are some sights and smells that take me back there and I still even get a little thrill of panic in my guts. It was the most profound experience of my life.
I saw him once years later across a car park. A friend had travelled from abroad to see me and we were having a day out where we used to live. He didn't see me. I almost fainted. I felt frozen to the spot and then I felt sick and hot and panic striken. I still felt ill that evening. That is how they get you. It's bizarre how one person can do that to another. I know if he has seen me he would have come over and started chatting and been as light and breezy as possible as if he is the nicest person in the world. He could turn it on and off like a tap. I feared this encounter but it didn't happen.
Leaving him was hell but staying would have been far worse. I knew he would eventually kill me. I know his parents thought we were still together two years later. I heard that on the grapevine.
I'm glad I experienced it now as I would never allow that to happen to me again or anything close to it. It sort of had to happen for me to be who I am .
You will go through a horrible time over the next few weeks and months. Be your own best friend. Be the kindest to yourself you ever will be. Eat good food, listen to good music and talk to others about it if you can so you can get it straight in your mind. It's almost as if you have to wait for the fabric of your life to change with the passage of time for you to realise he doesn't fit with that fabric any more.
One day you will wake up and not feel it all so acutely and then one day you will find that you have gone much longer than normal without thinking about him. You will take off from that point.
I was lost to myself and others for so long. I was like a moth beating myself against a lamp and tearing my wings to shreds to try and get it to work when for him it already worked the way he wanted.