Infidelity and ADHD

I am looking for advice or success stories. Long story short - I've been with my husband for 13 years, married for 11.5. We only realized he had ADHD last summer, and have spent the last 9 months learning a ton about it. I have been realizing how much it impacts our relationship and signed us up for the seminar from Jan - March, and had plans to work with an ADHD therapist once it wrapped. Unfortunately, my husband - unbeknownst to me - decided he was overwhelmed with ADHD and didn't like feeling like all the issues were his fault (I tried so hard to NOT communicate this, he has a lot of shame he is struggling with) and he decided to have an emotional online affair (with some sexting) starting in february. I found out one week after the webinar series ended, and he moved out a week later (his choice). I've spent the last few weeks in limbo, which him saying he isn't sure if he wants to work on things with us because it is overwhelming and he isn't sure we can fix things and he doesn't like how much of it is tied to ADHD. So he is in some denial, also struggling with hope. and still talking to his affair partner.

I am devastated, especially because he had another affair 6 years ago that I don't feel we properly healed (that one was a one night stand). However, doing the seminar series and reading Melissa's books have been like the heavens opening. Everything in our relationship finally makes sense! I have so much hope that if we can commit and dig in, we can ABSOLUTELY turn things around and get to a really good place.

What I am struggling with is 1) he won't end the affair yet and it is (maybe literally)  killing me and 2) he is feeling all sorts of things and is very unsure. I am looking for advice around how to take care of myself through this to extend my hope so we can (hopefully) at least have a chance to try, and advice around what I should do to support him through this. He has not responded well to me sharing what I am learning, he refuses to read the books, he barely paid attention to the seminar, so he just doesn't realize that there are tools and answers. However he does like to talk to me a few times a week and only wants to talk about things he deems as "not hard conversations." Which is confusing. I do not want to walk away without trying with the right tools. I know i cannot control him and he may well give up, which will be devastating, but I am hoping for advice on what i CAN do and especially for people who have walked a similar path, and if anyone has walked it and succeeded in healing and has any advice.