Well, you are receiving excellent advice from Job. She, among others helped me get through those early crazy days.
My h went through months of telling me he wanted to move out. When I confronted him on where he was going all the time and why he seemed out of it, he lied and said nothing was up. MLCers lie, they are sneaky and they are selfish. Weeks later my h confessed he had been apartment hunting but hadn't REALLY lied to me as he had not yet decided if he wanted an apartment??? He was trying to see what "felt right."
Cue eerie MLC music. MLCers operate on feelings and emotions not logic (as you are seeing.) My advice during this conversation is to keep your body and eyes quiet (no angry or antsy body language), speak quietly and calmly. Look him in the eyes (but he will probably avert his).
You can't control anything he is going to do. And he may not remember anything he says. My h told me I could sleep with other men and he would sleep with other women (?!?) and then didn't remember saying any of it the next morning. And I believe he didn't remember. You can't make things better/fix him but you can make them worse. Much of Job's advice points to ways to avoid making things worse: acting like his mother, telling him what to do, getting emotional discussing the relationship, discussing OW, etc.
There was a woman named Beatrice who gave me great advice in addition to Job's advice. Try to think of TED statements. These are statements that begin with "Tell me," "Explain to me" and "Describe..." So in a calm voice and body (very nonchalant) you may say w/ eye contact "tell me why you want an apartment?" "Describe what you are feeling." Then you listen and if you can, give quick, calm advice but only where necessary. Learn by listening. Mostly listen as you will learn most this way.
Through this method I learned my h wanted an apartment to "live life." Ok, so then I ask "tell me what 'living life' means?" (There's that "tell me" statement.) And he insinuated sleeping with other women. So then I calmly said (like a friend not a wife or mother) "didn't you already do that in life? Remember you were bored of it?" And then I dropped it. No arguing, no beating a dead horse, etc.
One thing I did, was to tell my h in a very calm way: there's no rush. No reason to do something rash. You have time." This seemed to talk him off the ledge in those days.
If you want him to stay, the key is apply NO pressure (through words, emotions, your body language, etc).
At the right time you can show him the spreadsheet and maybe say "there's no funds for this and also there's no reason to jump into this." Say no more. Listen. Then if he says something and you need clarification, go to the TED statements.
You're not going to like this next bit. I wouldn't go talking to him about his responsibilities with the kids or the house. He will run. My h is 1 1/2 years post BD and he just ignored me for 1 week because I very politely asked him to clean his dishes.
Worse yet, seeing what I saw of his odd behavior, I did EVERYTHING with the kids for almost a year. He was so out of it. I didn't want him having responsibility for my children. He would get lost driving, forget what day it was, etc. Just because he is their father does not mean he is the right person to care for them right now. I know that's not fair. But it's reality. If you were interviewing him for a babysitting job you'd never hire this person! You'd be better off picking somebody off the street. (My h is better now with the kids. He is more active in their lives, but not his old self with them, by any means.)
We are no longer dealing with a rational adult. You are dealing with a selfish teenager who can only think of himself. We have to try not to think of MLCers as an adults.
Bottom line is keep it calm, short, to the point. His attention span is short now. Once you make your key points, yawn and stretch, like none of this is huge to you, and then you leave the room first. That's right!! I was always yapping away and reasoning and things only got worse. When I made my quick points, yawned and moved on with my night my h gave me owl eyes. Once, after I left like this after a crucial conversation I could see into his room as it had a window to the outside. He sat in that chair for a full minute before he moved. He expected me to stay there and talk him to death (which is what I used to do).
Again, you can't control what he's going to do. Your best chance it to show him there is no pressure. Then you back off completely.
Get some exercise beforehand. It always helps. Sending you calm vibes.
Me 41, H 47, M 15 yrs, S11, S13 BD 1: 11/4/14 we work on it; really I pretzel myself BD 2: 3/31/15 H goes down to "dorm room" 8/15: H back to MBR 10/15: H back in dorm room 1/18: H files, now divorced