Mypoorkids - I am so sorry you've joined us, but happy you found the site. ((Big hugs!))
You have only two jobs right now. The first is imperative - the second highly advised, but as you can manage.
The first is your health! Eat, drink (stay hydrated) smoothies if food is too much, vitamins. Your immune system is taking a major hit right now. Try to get a little exercise, walking is good. Get through the day anyway you can, one breath, one minute at a time. Take all the hugs you can get right now and give them liberally to the boys.
Your second job is not to let the fear paralyze you and not to let the unknown control your choices. To combat the fear - you need facts (or at least to know what you could reasonably expect if it comes down to D.) Your WH is likely going to spazz out - losing his family and OW at the same time. You need to protect yourself, because his behavior will likely continue to shock you. Brace yourself and know this - A's aren't about the BS, not about something they did or didn't do. A's are about the sense of entitlement of the WS - period. Whatever he says about the marriage, remember - you were in the same M and you didn't cheat!
He has been lying for 2+ years - that is likely to continue, unless and until he truly realizes what he has done. Kicking him out is one step in letting him immediately feel the consequences of his recent decisions. Good.
Now gather all pertinent information taxes, Ira's, pension info, life insurance etc. Secure copies of these out of the house, with a friend.
How much is in the bank (you can reasonably take half). Where ever you are - you want to see an atty. Find out if you can file for Temp. support, what the procedure for S/D is in you state... You can usually do this in a free consult. Get a credit card in your name only - NOW (using the family income and credit).
This is not to say you are going to D. This is a precautionary measure to protect you and your kids, because right now you have no idea what your WH will do...
More hugs (((Mypoorkids))) Whatever happens - it does get better! Just hang in there!