Will I be able to cope on my own?
Hell yes!! You are coping at the moment with sn child in horrible circumstances - and living on your own you won't have the horrible circumstances.
Will I be frightened to live on my own with the children?
People used to ask me if I was frightened living on my own. No, I just loved having my own space and own home where I could live my own life, do what I wanted, eat when I wanted, and have absolutely NO eggshell flooring at all.
Will we cope financially?
Yes I am sure you will. You might feel 'worse off' in say a smaller house and initially on benefits and tax credits. But when I left xp (he had a very well paid job) I had less spending money and at times was totally brassic. But the fact was that all the money that came in was mine to spend as I chose. So I felt better off simply because I could prioritise my money how I wanted. So, you may not be able to buy the children a punnet EACH, but your money won't all be going on gin and tonic, on running his car, on taxis home from the pub.
Also, you said the tax credits go into his bank account when they should go into yours as main carer. You will get the tax credits, child benefit, paid to you and I think you will manage it very well. You can always post on mumsnet for tips on how to manage on reduced income you know those threads are always fab .
Will they settle in a new school/area?
I can't comment on that as my own worst fear when young would have been to move school. But a new area, away from grumpy moody dad? Do you need to ask?
Will H and his family make things difficult?
H will I think definitely. He has convinced himself that you are worse than useless as a mother. You'll just have to prove him wrong. His family? Well they may not actually step in and cause trouble, but blood is absolutely thicker than water so they may close ranks and take his side.
Will H try to get custody of the children as his family have money?
Yes he might try but personally I would cross that bridge when you come to it after you've gone. Would knowing that he would or wouldn't try for custody make any difference to your decision to leave? Thought not.
He works full time and you don't. You'd have to be an incredibly bad mother for courts to decide to give him custody. The fact that HE thinks you are a rubbish mother won't alter a court decision.
There does that help, god my fingers are on fire!!