Lisa in terms of your dd I am not sure what to say, maybe legally you can get some maintenance from him but I would think seriously if you would like to do this.
Personally speaking I'd rather get my fair share of the home and move on.
What are his legal responsibilities to your dd and what are his 'rights'. Yes, children are expensive and money is time, time with your dd, time away from work etc. However, will getting maintenance from him to pay for your dd mean he has an ongoing relationship with her? Do you want this?
I think he sounds like a very dangerous man and I would want free of him, away from him and for him to no longer have any claim to me or my daughter.
Also if he has made your life miserable in your home I would no longer want to live there. maybe just me. I would look into moving to a slightly different area even if you do buy him out. (So I would not run into him.) Maybe stay in same job and school if suits you but just a new area to live in not too far away.
These are just my views, check everything against a solicitor who understand domestic abuse after you speak to Women 's Aid.