There's someone on here who did it themselves - she recommends 2 books. I'm pretty sure one of them is the dummies guide to divorce.
I post the following fairly regularly:
Information is empowering. And will limit his power over you.
If possible find some friends/contacts that divorced well. Ask them for lawyer recommendations.
Get appointments with recommended lawyers. 2 reasons for this. It's important to find a lawyer you can work with. I got lucky with no 4. The other reason is if you've seen them he can't use them.
While waiting for appointments get all your and his financial information together:
Tax returns
Bank accounts
Salary slips
Savings accounts
Investments
Life insurance
Pensions
Mortgages
Debts
Assets
Get the house valued
This will enable a lawyer to tell you what you might reasonably receive.
Divorce for unreasonable behavior as cited in your op.
50:50 childcare is normal but sounds unlikely. There are sites like entitledto that will tell you what you might be entitled to from the state. There are also maintenance calculators.
Write 2 lists in terms of kids, house, cars, maintenance etc:
What you'd like (copy to lawyer)
What you'd accept (private)
Do not tell him what you are doing. Just get on with it quietly. The more of a head start you have the better of you will be.