I'm in the divorce process (being divorced as it goes) and I can assure you really don't need to 'prove' anything. The minute you decide you want to leave the marriage it is all but over bar the legal bit.
The quickest divorce is a 'fault' divorce based on one spouses' unreasonable behaviour. It doesn't even need to be true! So don't worry about having to prove it.
You (and that means he too) also cannot in all but the most exceptional cases, contest a divorce. The example my solicitor gave me of the two times she has successfully contested divorce was a woman who was set fire to in her kitchen by her husband, who then went on to file for her unreasonable behaviour.
That was considered sufficiently contestable and his petition was thrown out.
The legal bit is all about separation of the finances and arrangements for the children. Who did what to whom is not considered at all. You don't get 'compensation' for having a shit husband.
You have two ways forward: A so-called DIY divorce, whereby you agree the separation of the assets and the arrangements for the children between you, and then apply for the court's consent. This can also be done through mediation as well. Most people opt for this because it's much cheaper and there's not much by way of assets to divide/argue over.
Or a solicitor-led divorce. This is clearly the expensive way (cost 5K - 10K on average - but some are a lot more if they go all the way). Most divorces don't go all the way.
If you have a solicitor-led divorce, then you can choose to mostly use them to negotiate the finances/arrangements for the children, or they can apply for what's called a "Timetabled Divorce". This means the court puts in the key dates whereby you have to make full and frank disclosure of the finances/and make arrangements for the children. You go to court and your solicitor will tell the judge what issues are remaining to prevent settlement, and a judge will advise what needs to be done next. This is called an 'FDA'. If, after that, you still can't find any agreement, you go back to court for an 'FDR' - this time a judge will make recommendations of what he thinks each party will get should they not agree terms. If you then, still can't agree terms, you go to a Final Hearing. On this occasion, a judge will decide who gets what, when and how.
The vast majority of divorces never get much beyond the FDA.
I strongly recommend a book called 'Family Law Made Simple' by Gordon and Slater which explains the divorce process quite well.
It truly is nothing like you see in the movies where your character is attacked and you're cross examined by a ferocious rottweiller of a Barrister.
It is just endless arguments of how to split the finances and to make arrangements for the children.
I suggest your first step is to make an appointment with a solicitor, taking with you any financial documents in your name (but none that at in his name) and any knowledge you have of his finances (but nothing in writing). They will tell you what you're likely to receive in a divorce and whether or not, you should apply for an Occupation Order (on the house), a Non-Molestation Order (if he's going to be aggressive), a Spousal Maintainence Order (if you're financially dependent on him and he can afford it).
It sounds like you are absolutely right to be making the decision as you have. I wish you the best of luck getting out. Can I point you in the direction of two threads by a woman who is currently plotting to get away from an abusive relationship to inspire you.
www.mumsnet.com/Talk/relationships/2141514-How-far-can-he-take-the-stressed-from-work-excuse?msgid=49253165
www.mumsnet.com/Talk/relationships/2174553-Work-Stress-Err-dont-think-so-mate?msgid=49670117