Don't drop your house. It's your security. It's your home. Private renting is much less secure (I know this) and much more hassle. It never feels like your own in the way a council house does.
His housing is not your problem- nor is his money. Nor is his mental health (if he threatens to kill himself then call 999.) You owe this man nothing - he's threatened to kill and severely injured you in the past.
The thing is I’m a terrible mother. My eldest has severe MH issues because of my inability to be a parent.
Aww nonsense OP. xxxxx This bloke has mashed your self-esteem. I have MH problems and it's not my mum's fault (it is probably partly my dad's fault- but then again MH issues happen, they don't always have a cause, people can be born with the tendency to develop them.)
And no-one thinks you're a twat. xxx
it’s my fault and I know the eldest would be over the moon for me to leave.
If they feel like that about you then they should leave your home and get their own. People with MH problems can live independently- with support from services if need be.
I have let them down massively by staying in an abusive marriage so in effect I’ve abused them by doing so
No, it's not that easy to leave, especially when there's life-threatening violence, or the bloke changed the locks again and won't fuck off. If he does that again maybe call the police. A lot of women get stuck with abusive men and find it hard to leave for a long time. It's not like you haven't done things over the years to try and break free.
Please seek help again. xxxxx