Well. I am sorry for what you are going through. I was in a bad relationship for 19 years and stayed because I was afraid of leaving and because of the kids. Now that they are all grown up, they tell me things that make me wish I had left sooner.
That being said, what you're going through is tough. Maybe find a lawyer to give you some advice - are there any in the UK that give a free consultation? Might help make things more clear.
Anyway, good luck, it's not going to be easy but it will be worth it.