In your shoes as a DV victim I would try to extricate yourself with the minimum of fuss and legal costs.
Try to see it as a negotiation. You need to find your inner Trump and be a total arse.
Leaving with £30k deposit intact is reasonable in a house that hasn't appreciated in value. £35k is a good outcome. I appreciate you think as you've been paying a % of the mortgage you are owed more but in reality you have BOTH just been servicing the interest, you should see it as rent you would have paid anyway.
You are not living in the house but you are legally obligated to continue to service the mortgage. You have made your payment for this month. Tell him it will be your last. You will let the house fall into arrears and the bank can sell it.
To be clear - This is a bluff.
Tell him you are willing to sell your share in the house to him for £35k for a clean break. You will not be married to him any longer [presume you have no interest in further DV]
As he has barred you from the house you intend to immediately contact the utilities companies to say you have moved out. You can either have the services either put in his name or disconnected. Which does he want? Any reconnection fees will be his problem.
Be really short and firm, do not engage with conversation and back and forth. You don't have the funds, you need to act now. You are not going to give him weeks to delay and make a decision.
If you don't feel strong enough to do this. Find someone to do it for you. A sibling, a bolshy friend.