You've recognized the problem. I imagine your W has been telling you what her issues were, but in your position you weren't able to hear them. Her telling you her issues probably sounded like she was listing your failures. With your business in decline, you were scared and naturally became defensive. Your priorities got screwed up and you thought that by succeeding in business would solve all the problems, or at least give you the confidence to start working on your marriage. But now you've been slapped into reality and know that your marriage is what is most valuable to you. That is good.
You are here. The reason so many marriages fall apart is because people don't know how to be married. They don't have a plan or a system. Now you have one. And you have a number of great folks who have been working the system for quite a while. I know it may be weird that people are here for long time. That's because there are two people in their marriage. And one of them isn't following the system yet. But you just have to dedicate yourself to it and pray that your W will see the change in you and will become interested in it for herself. I hope you are reading the DR book.
Your W is crazy right now. Inside her head there is a roar of fear and anger and hope and guilt. She may act calm and decisive, but inside she is a storm. And she doesn't like it. And she blames you for that feeling inside. This is your OPPORTUNITY. This is how you may be able to get her to come back. But it will take a while. The OM is attractive because she doesn't really have a relationship with him. He is the pure promise of perfect calm and fairytale love.
You have time. Your W is giving you a recess from the marriage. You can stop worrying about what you did wrong. BUT you now need to focus on what you want to be as a husband. Being a good husband doesn't require your W, because being a good husband is something you do. So decide what kind of man you want to be. And start being that. Start practicing being that man. This is where the detaching comes in. To keep her beliefs alive, your W needs you to do all the things that bothered her. She needs you to be a bad person. She needs you to fight, and beg and cry and say you were wrong, and crawl after her and spy on her and get angry. When you detach, you will do none of those. You may feel like doing them, but you need to use your Mind and common sense and choose to not do anything.
Let her go. Let her be free. Be happy for her. Be happy for you. Be happy around her.
Right now, she is like a dog on a leash. You are holding her back and the more you pull, the more she will pull in the other direction. Let go of the leash and she has nothing to pull against. Yeah, she may run wild, but she will look over her shoulder and wonder why you let go. When she looks back, what do you want her to see? A whining, sobbing, angry man, or a happy, confident man?
That is why I think you are in a good place. All that stuff above is good stuff and will help you. And I screw it up and whine and cry and spy once in a while. But I am getting better at practicing what I've preached above. And my W is still running. But she does look back now and then.
So, if I were you, I would (and I have done these, mostly): 1. Detach. Control your emotions. Don't let her actions control what you do or feel.
2. Go out with people. Twice a week, at least, go do something with other people.
3. Spend more time with your daughter. Really enjoy her.
4. Compliment 3 people every day. Don't do it to make them feel good. They maybe grumpy or sad and not respond. Do it because you are a nice guy who pays attention to people.
5. Say one thing nice to your W everyday. You have to do this EVERYDAY! No forgetting. And it has to be and sound undeniably sincere. You can only compliment her looks twice a week. Everything else has to be about what she does.
6. Make a list of how you would be if you were the husband you want to be. But none of the items can refer to your W. For example, don't write, "I would make love to my W everyday." Instead write, "I express my love physically and passionately."
7. Start doing the things on your list. Think of ways that you can do them without your W. for the example above, you could start hugging people or doing the 2-hand handshake.
8. Get your business in shape. This doesn't mean stay there all day and night. Get it in order so you DON'T have to be there all the time. If you do this you will stop resenting it as much.
9. Say to yourself, "this is where I am. Now what can I do that will actually make it better?"
10. Start doing small scarey things. Little challenges, just outside your comfort zone. Talk to that pretty woman standing in the Fruit and Veggie section without trying to pick her up. Try a new sport. Take a dance class and laugh through it. Look for little challenges and do them. You need to build your self-confidence and little challenges are the best way of doing it.
I know that is a lot, but I think it will help. It all helps me when I do it. You are going to have great and terrible days. For the terrible days, watch something funny. Watch cat videos and think how hilarious it is that a grown man is watching cat videos.