"Like I know you'll all think he is awful but when he is sober he is a completely different genuinely. I am also worried that if I leave he will get much worse and I am worried our daughter might still have to stay there and might get hurt".
Its likely he is never properly sober but on a comedown from alcohol. Abusers too can be "nice" sometimes but that is all really a part of their nice/nasty cycle of abuse which is a continuous one. You would not in any case leave your most precious resource here, your DD, with her drunk father overnight. Why would she at all have to stay there; this is supposition on your part so likely wrong too.
Your responsibility lies with you and in turn your child, not him. No, no and no.
You are playing out the usual roles associated with your alcoholic; those of codependent partner, enabler and provoker because you never forget. I also think you are confusing love here with codependency. This relationship is over bar the shouting and you are going to have to dig deep now in order to get him out of your day to day lives. It will not do your DD any favours at all to see you as her mother being abused by her drunkard father. What do you also want to teach her about relationships and what is she learning here?. Think about what you learnt from childhood; you yourself have been left with a lot of damaging crap that still harms you to this very day and it needs to be unlearnt. I would urge you to also contact Womens Aid and get their advice as to how to leave safely. The Freedom Programme is also worth doing online; you need this too.
Re your comment:-
"My dad has never been in my life and I'm really sad about that and I want to do everything I can to help him be a good dad and I know he can."
I am so sorry your dad has not been in your life but that was his choice ultimately and is NO reflection on you. You were but a child at at the time and the adults in your life let you down abjectly. You cannot help this man now become a good father; again that is his choice and is not yours to make for him.
Do you have any idea what a mutually respectful relationship is; I do not think you do mainly no-one ever bothered to show you one. And this relationship you are currently drowning in is not it either.