I don't generally say this to someone so new to this. I am going by your words and you do seem to have gained clarity sooner than most. You have been given the gift of time. Time to figure out exactly what you want to do. Only you can know what direction you ultimately want to take.
Marriages have survived infidelity. It takes both partners wanting the marriage to work out and it's not easy. But of those M's that have survived, I do hear that they are better and stronger.
The first thing you have to do is own your part in the breakdown of your M. You sound like you are doing that. The next thing is that you have to do is forgive yourself. No, the choice to have an affair is fully on your H and there is no excuse for that, but forgiving yourself is the key to being able to forgive him.
In this time continue to work on yourself for you. Make sure your changes are for you and are permanent. It can only benefit you whatever happens in your sitch. If you do R you'll need that strength and clarity you've gained.
There is a saying that MWD has and it's, 'believe nothing they say and only half of what they do'. Your H is so fogged up right now he doesn't know which end is up. Validate what he has to say. It doesn't mean you agree with him, only that you agree he has a right to feel that way. Saying I'm sorry you feel that way, or I understand why you might feel that way or some such thing lets him know that you are listening to what he has to say.
MWD also says do more of what works. If you've seen your H take notice of your 180's continue that if you want to.
You sound as if you're a natural DBer. Have you read Divorce Remedy? If no, get it. If yes, read and reread.
I believe you'll be better than OK no matter which way your sitch turns out.
