Be. Careful.
The same character flaws that allow a person to commit infidelity also allow divorces to be very difficult.
I could have wrote something similar in September 2018, after my xWW and I agreed to get a divorce. Ironically, people here warned me to be careful, just like I am warning you, about my now xWW. I ignored them, much like you are likely to ignore me. To be clear, I really hope that I am wrong about this.
After verbally agreeing to have a quick, easy, and amicable divorce, my xWW then proceeded to initiate an exceptionally high conflict divorce that has (so far) cost about $60,000 (combined) and it's still climbing (I am appealing a portion of the judge's decision).
And, unfortunately for xWW, all of those legal expenses did nothing but make life difficult for her, for me, and for our children. She "won" on the child custody issue only (i.e., she has the kids for 70% of the overnights), but it actually cost her financially (a lot). She is currently receiving child support and alimony that are slightly less than I offered her in December 2018. Meaning, she felt entitled to more than her fair share (wayward thinking, amiright?) but she only got her fair share because that's the law. Admittedly, I had to have a lot of patience and courage to have spent all of that money to get a judgment that was fair (or close to fair).
So, more specific advice:
0. Take care of your kids, first and foremost. This is a scary time for them and they are even less responsible for your divorce than you.
1. Do not express any anger towards her at all if you can help it, especially with your writing.
2. Keep all documentation of everything that you can. People lie, either intentionally or because their memory is biased.
An irrelevant example from my divorce is that xWW agreed that we should get our son (age = 9) a cell phone so that he could play games in the car and so that he could call us. She claimed, in court, that I got him a phone without her permission and that I was a bad father for doing so. The reality is that she agreed to getting the cell phone via text message (I would have shown this evidence in court, but our trial literally had nothing to do with my parenting abilities because we had already agreed on custody.
3. Consider getting a voice activated recorder.
It's not uncommon for people to say things that you would like recorded. Make sure that you live in a one-party consent area (i.e., one party consent means that you can record conversations with another person without their permission... you cannot, however, record conversations between other people without their permission).
4. Learn everything that you can about child support and alimony in your area.
My xWW wanted more custody because she wanted more child support (i.e., more money for her). In some locations, alimony has specific rules. In other areas, the rules are murky. In some places, infidelity is a disqualifying factor for alimony; other places are "no fault." This will be particularly important for you because you were the "breadwinner" and alimony is intended to help out your ex in situations like this... which means that she might play the "woe is me" card as much as possible to get as much alimony as possible.
5. I would get her moved out of your house as soon as possible. No one claims that in-house separation is enjoyable... and it can possibly lead to issues that affect your divorce.
6. Listen to your lawyer. Teach your lawyer all of the pertinent details.