First, I'll say listen to COG and AmyC. They've been through, and seen a lot. They are not making stuff up.
Second, I must admit to not reading every word, as I do have other plans for the day! And I also admit to not being expert, but I've been reading and thinking about a lot of this stuff for a long time, and I have been getting a feel for what's a good idea, and what's a bad idea.
So, here come some 2x4's!
First, I think you have to get past some denial issues. You were drunk when you wrecked the car, but you didn't wreck the car because you were drunk? Doesn't fly, even if the car was sitting still, and it really wasn't your fault. You just can't mitigate it that way. It sounds to me like you are still trying to duck the responsibility, and that's what it has sounded liek to her, too! Then you say you didn't really snoop! So what is calling unknown numbers, doing a reverse phone number lookup, and trying to find out about a person's job? There's no way around it, you snooped. Given those two items, I wonder if there isn't some degree of denial about your responsibility for the trouble your marriage is in. It's totally understandable, but the more you can realize your part, the better your chnace of doing something about it.
Then second thing I noticed in reading through these posts is an almost complete focus on her, and very little on you. Her rings, her moods, her phone, etc., etc., etc. There is only one person you can control in this situation, and it is not her.
The moving out question is a tough one. Usually I would say it was a bad idea, but with you job situation, and transportation, I can see it bing very hard not to. Also, once you have committed to it, backing out of it seems to me that it might be a very aggressive move. What I think you have to do is make it clear that you are doing it because of the house arrest, and that you WILL be moving back into the house afterwards. I don't know your state laws, but I think you will want to make certain that you don't lose any rights to the house, etc., or any standing in the marriage (abanonment and such) by leaving. That would change things.
When you come back, you might have to consider the living arrangements in the house. Living in the same room migh be a bad idea, but you need to do better than the couch. Anyway, that's a bridge to be crossed later.
On the affair and snooping.....there's one question you have to answer. No one can answer it for you. If she is having an affair, are you going to file for divorce? If not, there is absolutely nothing to be gained by snooping, and obsessing over what she's doing, or not doing. That's because it doesn't change your course of action. Remember, the affair is NOT the cause of you current troubles. I think that's pretty clear. 'Using' any information you get from snooping is absolutely guaranteed to drive her further away. In some ways the less you know the better. Some people will say that this position makes you weak, and used, but this isn't a contest where there is a winner and a loser. you are not trying to beat her!
I'm not saying at all that she's right in all this, but here's one more thought I got while reading this. Somewhere along you mentioned how much she has hurt you in the past 2 months, and how unfair it is. Remember, from her current perspective, you've been hurting here for a large part of 16 years, and I'm she she thinks that's pretty unfair. Again, I'm not saying that her perspective is right, but it is what she is feeling. You can disagree with the rationale behind the feelings, but the feelings are real.
The mortgage....having your name off the mortgage can't hurt you at all, that's the debt side of the equation. You just can't sign your name off the deed. Of course, check with a lawyer to make sure. If things do get to the point of splitting assests, even in separation, make sure you have good legal advice. Some things that seem obvious are not!
I know there were other thoughts I had. Here's one.....GAL does not mean flirting with the pretty young things! That's called being disrespectful to them, your wife and yourself! I think you were joking, but there have been cases around here...... Anyway, GAL is doing things to improve yourself, for yourself. It could be a hooby, a class, a sport, working out, almost anything.
Anyway, for now, what can you do?
Truly understand the part you played in this. You were a provider for years, but I think you were not a husband and father. In this area, I unfortunately have some experience. I'm still working on understanding it, but I think the point is that there were things we should have been doing that we didn't realize were important.
Strengthen yourself. The obsessive, almost panicky you is most likely not very attractive to you W. Stay sober. Don't talk about it, just do it. It sounds like you have agood start, but I think it will take more than a couple months for this to be a permanent change.
Be ready for the long haul. This is almost certainly going to take many months, more likely more than a year, two, or more, to fully and completely resolve. Even in the best case I think it is months before things even move in a positive direction.
Remember that you can't control your wife. But also remember that she can't control you. You are responsible for your actions, she is responsible for her's. And, teo wrongs do not make a right.