Oh OP, I'm sorry you need to walk this path. You won't want to hear it, but it is time. A lot of time, a lot of anguish, many bumps in the road, stress and tears. It is time that it takes.
I'm 18mos out and for the first time this weekend, I had this feeling of contentment. I feeling of 'I won' I appreciate its not a game, or a war (although that is debatable in my situation) but it just washed over me.
Infidelity is very hard to navigate, the emotions that come with that are intense and justified.
Firstly, eating and sleeping will be difficult, but eat when you can and rest when you can, you will need strength.
You also need to be practical, controlling what you can will help focus when you can't control what is happening around you.
A good support system is crucial for now. To help you and support your family.
So, house, money, children.
Home, is it mortgaged/rented. If mortgaged can you afford to buy him out? How much is left to repay, how equity is there and can you mortgage what you need?
Rented, is he on the tenancy?
Money, do you have access to funds? SAHP? Job? Part time/full time? Increase your hours?
Documents, mortgage statements, bank statements, pension statements, debts? Benefits, entitled to is a website that will help work out what can be claimed if anything.
Children, regular consistent contact with other parent. Maintenance, if you know how much he earns, pop on to the CMS calculator and work out what he has to pay.
There is going to be bundles of advice on these boards, but you will ok