I commend you. You are doing the right thing. You are giving your spouse the freedom to choose and your marriage the opportunity to grow.
Here are a few things that helped me, or could have helped me:
I do not recommend this for an abusive relationship.
I needed a MC asap when I first discovered my wife's affair. I could not trust anyone, not even myself. It killed me that we needed to wait 7 days before we could talk to anyone. Reserving a few slots with a MC and/or IC might be helpful for your spouse. Maybe your IC will speak highly of you to help your spouse to understand that you are on the right path, that you are not that person anymore.
TT kills, but overload kills too. Give him a time line first. When he asks for nitty gritty details, remind him that he can always ask for them later because you will always tell him the truth. I often asked for the nitty gritty details only to test my wife's willingness and strength, but then suffered from the details. Show your willingness and strength immediately, and don't waver. Maybe he won't ask for everything if you do.
Don't lie about anything, not even about general things in life, not even a white lie, not even to a salesman, not even to be "nice" to someone. Be truthful in every aspect of your life.
Don't clam up, don't become defense, and don't fight back during discussions, and take full responsibility for your affair, and demonstrate to him that you are on his side. Be willing to talk when he wants to talk. Ask him if he wants to talk. Do this so he believes you are always willing to tell the truth.
Don't suggest that you know how he feels. Ask him.
Don't tell him what to do, or tell him he's wrong. Instead, recommend and show what you have read or were told about that he might also consider. He needs to make his own choices and reach his own conclusions. He may not trust your opinion and do the opposite. Tread lightly.
Don't use "you" (your BS) in your reasons/answers. He was not the reason for your affair.
Don't use "but" and "however" in your reasons/answers. He may become sensitive to semantics.
Don't use "mistake" in your reasons/answers. Calling it a mistake gives little reassurance that you will not do it again. Rather, say that your affair was based on messed up logic, which you understand now.
Remind him you are not "that" person anymore. Ask him to join your journey to a place further away from that person. You will do it regardless. My wife often told me this (late but never the less) and it helped me.
Remind yourself silently that you can always work on the problems of the marriage and problems of your spouse later, if needed, but not now, not while he's still in shock. He won't understand yet.
Agree with having a few books on hand, if he chooses to read them.
Contact him frequently by texting, calling, emailing, etc. so that he knows you are always thinking about him, because he will be always thinking of you. Let him know you are his top priority and you are there to support him.
Expect drastic mood swings and triggers. So compassion through them. Tell him you are sorry for what you have done to him, full sentence.
You are doing the right thing.