Sorry in advance if I'm too blunt but it is trying to be helpful. You deserve way better than all of this and I hope this will help. .
You have a big advantage you don't recognize here. He is feeling guilty and seems rather
desperate for his new freedom. That puts you in a much better position than many women in a divorce. I think you could get either of the properties. (or both and let him look for some other place) Real estate might be hard to sell if you needed cash though, so he still needs to cover the other expenses.
Watch 1 st Wives Club. It will help you. You need to get your needs, and the kids needs covered.
Any extra you get is the screwing he gets, for the screwing (cheating) he got.
Use your own lawyer too. You need somebody that knows the system inside out protecting your interests. Getting the divorce official while he is feeling guilty is probably smart. Make sure he is legally responsible for :
child support - paying through the court is best, in case he ever tries to squirm out of it.
Life insurance policy on him with you and the kids as beneficiaries
the children's medical insurance and all deductibles, co-pays & expenses that are not covered by it
your medical insurance, since you have to stay healthy for the kids
schooling expenses- including college tuition till they are 25.
alimony
mortgage, electric, phone, oil/firewood, water, trash, all the normal bills, etc.
Credit cards paid off- then start fresh in your name. Don't ever run them up high, but getting a good credit history is a help.
job training, licensing fees, uniforms, any expenses for you to go back into the work force
(Sorry- but this needs said) - Dr expenses for you to get tested for std's since he was going behind your back. Women don't always show symptoms, but you need to know you are safe. Tell the Dr he cheated, and you want tested for everything.
The court cost and lawyers fees for both sides! You wouldn't need a lawyer either if he hadn't decided he wanted out, so it is his job to pay for it.
A good lawyer may think of things I didn't know to tell you. This sounds like alot, but if he was raising them with you, they would be
normal expenses. Him changing his mind doesn't take the responsibility away. You deserve better than this, but at least make sure you are able to get by fine without him.
Go read you old journal entries if you have a weak moment and start thinking about living with, or near his parents. You weren't happy then and it would be worse now. Living around them would also be a daily reminder of him when you need to be able to move on.
When you have moments where you need to release some anger over what he did- they are
not the people to do it with. Because sooner or later, they will start missing their boy and feeling more forgiving of him. Then they would be stuck in the middle and find some excuse to get mad at you.
They love you, but let them wish you were in their lives more- instead of feeling like you're in the way of having a relationship with their son. It will remind them their son was a jerk, but you'll still look good. You can visit them once in a while so they can see the grandkids, or let them visit you, but don't live there.
If you are attached to the 1 acre because it was your families land - don't let him have it. Many people regret selling land that was in the family later, so be careful. If you want to sell it- he can buy it from you at full market value. Remember he may move that girl in wherever he lives- so make him PAY if he gets it.
That 10 acre property sounds like it was important to you, but would it be easy to start over living up there? You said once that you knew somebody that really wanted it. Maybe you could sell it to them, and get property that's easier to farm/homestead if you wanted to. It's a buyers market if you have CASH $. You might see a place that's just right, or make one of your properties fit your needs better.