Hi Gravycake,
I would like to start over if we can. Now that you have come forward with all the details, I think there are a variety of ways we can help you move forward.
First, your last DDAY is Mid-September. Timeline is always important to be able to relate to where you are in the process.
Secondly, it's clear to me that you must have felt you had feelings for the AP. This is common, I certainly went through that as well. I can only draw a conclusion that you may be going through withdrawal from him at the same time having this experience at home. While we do bring this on ourselves, it doesn't make the pain and confusion less during this time.
So, I will simply make a few recommendations from someone who has been where you are.
1. Commit. The back and forth is really tempting in the beginning. During the A we often re-write our marital history (you are unlikely to think that is the case at this point). Read about cognitive dissonance. We justify so much because the A is a strong draw but it goes against what we have learned as right. For me, I committed fully, No Contact means no further hurts for anyone involved. I told everything. I worked through the pining and confusion in IC. It's not an easy time to navigate.
2. Start recognizing the reasons that you wanted to escape your life. What are your Whys? These should be things internal to you. You didn't cheat because of your marriage, your husband, etc...you cheated because you wanted to. Why? There are all sorts of standard answers that will help you dig. Here are a few common ones to start with:
Entitlement. Usually there is some sort of "I deserve this". Why did you feel you did? For me, I had dedicated my life as wife and mother, I had a tremendous amount more responsibility than my husband. I told myself I deserved something fun for me. The reality is, when I dug deep on this I realized that I had placed so much of that on myself. This is an example, you have to find what is true for you so you can fix it. I had to grow boundaries and learn to say no.
Validation. This is a big thing in an Affair. What did it do for you? Knowing that he was feeding whatever that was makes you start to understand that your feelings were not about him but how he reflected back to you the way YOU wanted to feel. That's not a genuine thing.
More _______. What were you looking for more of? For some it might be sex. For others it might be romance. For some it can be power, etc.
Keep looking for all of these things and then start creating a list from that of things you need to change. This will morph and change over the next year.
As for dealing with your husband, don't trickle truth him. Be calm. Don't be defensive. Don't defend the AP, your H needs to know you are on the same team and not AP's team. Make sure all your work aligns with the goal. If the goal is to keep your marriage then everything you do needs to align with that. If you aren't going to commit then just make the break now, no since in torturing your husband. I will tell you that I leaned a little that way early on because of all the self brainwashing I did.
Read all you can about infidelity, you will quickly learn what you have gone through and experienced is not unique to your situation.
And lastly, gosh try and see that your husbands rage is just coming from a deep sadness. Unless he's really over the top with it in a way maybe we don't understand, then just know this is completely normal. It might not have been your reaction to his infidelity, but it's a normal reaction. I think a betrayed husband especially has a hard time not using their anger as a bodyguard for their sadness. He feels humiliated, emasculated, scared, shocked, sad, angry, betrayed, and he doesn't know how to process all these emotions. When he lets it out, tell him that you are sorry that you have done this to him. Be there for him, try and concentrate just on him.
If the situation escalates or if you have children at home that you need to protect from these outbursts, then the two of you might consider one of you leaving the home for some period while this gets navigated.