I am so sorry you have had to be come here, but at least it’s a place where you can get some good advice.
I’m not sure if I’m the best to advise on this but I can give you some starters in regards to the MB process.
Your M can recover.
Many people have done it, I'm working on it. It isn't easy, and not everyone succeeds, but as long as you are both working on it, your chances are very high. A lot of what I have here is from a number of very experienced posters which I have collated for you so I hope it helps.
Read What Are Plan A and Plan B? after reading the "Basic Concepts" links below.
Plan A and Plan B You need to start Plan A with the help of a marriage counsellor (see item #2, below)if that is possible. There are a couple terrific posts about Plan A that are worth reading at: Plan A, Doormats and Love Busters by Zorweb and Cerri on Plan A, which will help you avoid some of the common pitfalls. Your chances of saving your marriage and actually making it better than before are still good. But, whether your spouse is "on board" or not, you should do three things:
1.) Learn. The most important and helpful source of information for many has been the book 'his needs her needs' by Willard Harley (hereinafter referred to as 'HNHN') available at the Bookstore, Amazon.com, and bookstores all over. Some say this book is one of THE best books on the market for helping one get to the root of "the message of the affair" (BUT YOU HAVE TO DO THE QUESTIONAIRES!). It (along with the Basic Concepts section of this site) is also helpful for giving you a vision of what a great marriage should look like. The approach of HNHN to this problem is that the best defence against affairs is to have a great marriage.
So that you can get started right away, while waiting for SA to arrive in the mail, read everything in the Basic Concepts section of this site. Next, read all the Q&A's on infidelity on this site. They are found at How to Survive Infidelity
The phrase "the message of the affair" is from the book "Torn Asunder", by Carder (hereinafter referred to as "TA"). Some here think this is the best book on affair recovery they have read. In particular it deals with the two different paths the recovery of the betrayed spouse (BS) and the wayward spouse (WS) need to take, and deals w/ remorse in a way that I prefer to HNHN. Read it together, if your spouse is willing. If not, go through it yourself. If you or your spouse has issues with control, you might also want to read "The State of Affairs", (SOA) by Todd Mulliken, which also treats the remorse issue similarly to TA. SOA also deals with "the vision thing" for marriage, which is not so clear in HNHN.
2.) See a marriage counsellor. This is hard. You need help. These boards are populated by amateurs. MC’s should be professionals. There is a difference. They can help deal with issues the books don't cover, and customize things to your individual situation. That said, there are lots of bad MC's in the world. Read, and take to heart, How To Find A Good Marriage Counsellor. You do not want an MC that is going to teach you how to live with an awful spouse, or how to adjust to divorce. Too many of them do, as is documented here: Hazardous Counselling. Reading that link may scare you off counselling, but it should give you some good ideas to ask a potential MC before you start w/ them, so you can avoid those that give you the wrong answers. You need one that is committed to helping couples have great marriages, and knows how to do that.
How to Find A good MC You are on an emotional roller coaster right now, and there will be times that you will think it would be best to just divorce your spouse and go on with your life. Though there are no guarantees, recovery IS possible, but it takes time and effort. You will hate yourself if you don't do everything you can to make that happen. Give yourself the time you need.
3.) If you are a person of faith, getting your spiritual life in order may be of great help and a great comfort so if it works for you then get on it.
STOP thinking about what SHE needs to do, since you can't control her, anyway.
You might also want to read through: WAT's Quick Start Guidelines for Betrayed Spouses, but keep in mind that we are all amateurs. Get the books, read the articles, and see a GOOD counsellor - you need the best help you can get.
Harley, who has helped THOUSANDS of couples through this process, lays out his program in the following link: How to Survive Infidelity You will find that I mostly followed his plan. It works & I am A FWW!!!
How to survive Infidelity